Bringing and Defending a Section 1983 Claim: A Practical Guide

Summary. This guide takes a § 1983 case from the first client meeting through the fee petition, on both sides. It covers the intake screening that identifies whether a viable federal claim exists, the very short state notice-of-claim deadlines that destroy parallel state claims, the preservation letters and public records requests that must go out within days, drafting a complaint that survives a qualified immunity motion, the Monell discovery plan that determines case value, the interlocutory appeal that will delay everything, damages proof, and the fee petition that is frequently worth more than the judgment.

Two things about civil rights practice are true at once, and both should be said at the first client meeting.

The barriers are real. Qualified immunity, Monell's causation requirement, the Heck bar, and the Eleventh Amendment defeat a large number of cases in which something genuinely wrong happened. A lawyer who tells a client otherwise is setting up a betrayal.

And the cases that survive matter enormously, both to the client and beyond, because 42 U.S.C. § 1988 makes it economically possible to litigate a claim worth $50,000 for three years, and because the discovery in a Monell case is frequently the only mechanism by which an institution's practices are examined at all.

This guide is about doing that work well.

Part 1 — Intake screening

Answer these in the first meeting, in this order.

1. Was the actor a state or local official acting under color of law? If federal, § 1983 does not apply and Bivens is now effectively unavailable in most new contexts after Egbert v. Boule, 596 U.S. 482 (2022); consider the Federal Tort Claims Act instead.

2. What constitutional right was violated? Name the amendment and the specific doctrine. "They treated him terribly" is not a claim. "Excessive force under the Fourth Amendment, measured by Graham v. Connor" is.

3. Is there a criminal case? Pending or resolved? A conviction may trigger the Heck bar. A pending case means the client should not testify and the civil case may be stayed.

4. What are the deadlines?

The § 1983 limitations period — the forum state's personal injury period, usually two or three years.
The state notice-of-claim deadline, which may be sixty, ninety, or one hundred eighty days and which bars the parallel state claims if missed. Calculate this first, in the first meeting.

5. Is there video? Body camera, dash camera, surveillance, bystander. If so, when does it overwrite?

6. Who is the right defendant? Individual officers by name where known, plus Doe defendants; the municipality or county; and, for state actors, the official in an official capacity for injunctive relief only under Ex parte Young.

7. Is there a clearly established precedent? Search the controlling circuit for factually analogous cases before accepting the matter. If none exists, the case is materially harder and the client should be told so.

8. Is there a Monell theory? Prior incidents, complaint history, a written policy, a policymaker decision, or a training failure. This is what makes a case valuable.

9. What are the damages? Physical injury, medical costs, lost income, emotional distress, loss of liberty. Note that a nominal-damages case has value only through fees, and after Farrar v. Hobby, 506 U.S. 103 (1992), a technical victory may support no fee at all.

10. Does the state have its own civil rights statute without qualified immunity? Several do, and where one exists it may be the better vehicle.

Part 2 — The first week

Send preservation letters to the agency, the city or county attorney, and every private camera owner near the scene. Demand preservation of:

All body-worn and in-car video from every officer, activation to deactivation
Dispatch audio, CAD entries, and radio traffic
911 call recordings
Booking, sally port, and holding cell video
All use-of-force reports and supervisory reviews
All incident, supplemental, and field interview reports, and officers' handwritten notes
Personnel and internal affairs files for each involved officer
Taser deployment logs, firearm discharge reports, and early intervention system records
Any surveillance video from adjacent premises

File public records requests in parallel. They are free, they run on a statutory clock, and they reach material a defendant would otherwise fight over for a year: use-of-force policies, training curricula, complaint statistics, consent decrees, settlements, and disciplinary dispositions where disclosable. See Requesting Public Records and Challenging a Denial.

Serve the notice of claim if a state-law claim will be brought. Do this immediately; it is the deadline most often missed.

Document the injuries — photographs the day of the meeting and again over the following two weeks, plus complete medical records.

Canvass for witnesses before their accounts consolidate around the official narrative.

Coordinate with criminal counsel on plea posture, testimony, and timing. A plea entered without consulting civil counsel can destroy the civil case.

Part 3 — Drafting a complaint that survives

The qualified immunity motion is coming. Draft for it.

Plead facts, not conclusions. Every fact that will matter to the reasonableness analysis: the time, the distance, the words spoken, whether the plaintiff was restrained, what the officer could see, how long each event lasted. Post-Iqbal pleading applies with full force here — see Motions to Dismiss Under Rule 12.

Identify each defendant's conduct separately. Group pleading — "Defendants used excessive force" — is a leading cause of dismissal in multi-officer cases. Say who did what.

Plead capacities explicitly. Individual capacity for damages; official capacity only for injunctive relief against state officials.

Plead the Monell theory with facts, not a formulaic recitation. Prior incidents by date and description; complaint statistics; the policy language; the identity of the final policymaker; the training deficiency and how it caused this violation. A Monell count that says only "the City maintained a policy or custom of using excessive force" will be dismissed.

Plead the clearly established law. It is not required, but citing the controlling circuit precedent in the complaint frames the qualified immunity fight from the outset and signals that the case has been researched.

Add state-law claims under supplemental jurisdiction, 28 U.S.C. § 1367, including any state civil rights statute — and confirm the notice of claim was served.

Include Doe defendants with a plan to identify them in early discovery before the limitations period runs; relation-back for newly named defendants is a recurring trap.

Part 4 — The qualified immunity fight

Expect it at the pleading stage and again at summary judgment, and expect a motion to stay discovery in between.

Opposing it:

Define the right at the appropriate level of specificity — specific enough to match the precedent, general enough to cover the facts. This is the central craft of the practice.
Marshal the closest analogous precedent from the Supreme Court and the controlling circuit. One well-matched case is worth twenty loosely analogous ones.
Argue the Taylor v. Riojas route where the violation is obvious enough that no prior case is needed. 592 U.S. 7 (2020).
Resist the discovery stay, or seek narrow discovery limited to the immunity question — video, reports, and the officers' depositions.
Emphasize factual disputes, which cannot be resolved on qualified immunity at summary judgment; the defendant must take the facts in the light most favorable to the plaintiff.
Remember the municipality has no immunity, so the Monell claim proceeds regardless.

Asserting it:

Move early, and move on the pleadings where the complaint is thin.
Frame the right narrowly and identify the absence of controlling precedent on these facts.
Move to stay discovery pending resolution.
Preserve the interlocutory appeal, which is available as of right from a denial on legal grounds and will add twelve to twenty-four months.

Part 5 — The Monell discovery plan

This determines case value. Build it deliberately.

Documents to demand:

The complete personnel and internal affairs files for each involved officer, including all complaints regardless of disposition
Five years of use-of-force reports for the unit or department, in a reviewable format
All complaints of the same type, with dispositions and any discipline imposed
Training curricula, lesson plans, attendance records, and certifications for the relevant topics
The policies in effect on the date, and all revisions before and after
Early intervention system records and thresholds
Prior lawsuits, claims, and settlements involving similar allegations
Consent decrees, monitor reports, and Department of Justice findings
Supervisory review documentation for the incident and for the comparators

Depositions that matter: the involved officers; their immediate supervisor; the internal affairs investigator; the training officer; and a Rule 30(b)(6) designee on policy, training, discipline, and force reporting practices. The 30(b)(6) notice is where the Monell case is made or lost — draft the topics with care.

What you are looking for: a pattern and notice. Prior similar incidents, complaints that were never sustained, force that was never reported, training that omitted the relevant scenario, and supervisors who knew. Connick v. Thompson, 563 U.S. 51 (2011), makes clear that a single incident will rarely suffice; the pattern is the case.

Expect resistance — privilege claims over internal affairs files, officer privacy statutes in some states, and burden objections to multi-year report productions. Litigate these early; they are the case.

Part 6 — Damages

Compensatory: medical expenses past and future; lost income and earning capacity; and emotional distress, which is often the largest element. Prove it with the plaintiff's testimony, family and coworker testimony describing specific changes, treatment records, and where warranted a mental health expert. Generic testimony about being "upset" is worth little; specific, corroborated changes in functioning are worth a great deal. See Proving Damages in Civil Litigation.

Loss of liberty damages for wrongful detention, typically measured per day with reference to comparable verdicts in the district.

Nominal damages where a violation is proved without compensable injury — worth pleading, because they establish prevailing party status.

Punitive damages against individuals only, requiring evil motive or reckless indifference. Not available against a municipality.

Wrongful death and survival claims are governed by state law incorporated through 42 U.S.C. § 1988(a), which means the state's survival statute determines whether the decedent's own claims survive and who may bring them. Check it early; some states' statutes materially limit recovery.

Part 7 — Settlement, including the part that is not money

What drives value: the video; the severity and permanence of the injury; the officer's prior history; the strength of the Monell evidence; the jurisdiction's verdict history; and the fee exposure under § 1988, which is frequently the largest number on the defendant's ledger.

Structure the settlement to include what money cannot buy:

Policy changes — mandatory force reporting, supervisory review requirements, de-escalation training, body camera activation rules.
Training commitments with defined content and audiences.
Data reporting — publication of force and complaint statistics.
An acknowledgment, where the client wants one, negotiated carefully.
Non-confidentiality, or narrowly drawn confidentiality. Public entities settling with public funds face records-act pressure toward disclosure, and a plaintiff who wants the outcome known should say so early.

Fees are frequently negotiated separately, and a defendant proposing a lump sum inclusive of fees is creating a conflict between the client's recovery and counsel's fee. Address it directly and document the client's informed agreement to any allocation.

Part 8 — The fee petition

Often the largest single component of the case.

Build it as you go, not at the end:

Contemporaneous time records with task descriptions specific enough to audit.
Support for the requested hourly rate: prevailing rates in the community for lawyers of comparable skill and experience, established by declarations from other practitioners, fee awards in comparable cases, and surveys.
Results obtained, documented — the recovery, and any policy relief.

The framework: Hensley v. Eckerhart, 461 U.S. 424 (1983) — reasonable hours times a reasonable rate, adjusted for results. Anticipate the reductions: block billing, vague entries, excessive staffing, clerical work billed at attorney rates, hours on unsuccessful claims unrelated to the successful ones, and travel.

Two rules that decide fee petitions. Buckhannon, 532 U.S. 598 (2001) requires a judgment or court-ordered consent decree — a defendant's voluntary change does not make you a prevailing party, which is why settlements should be entered as consent judgments or dismissals with retained jurisdiction where fees are sought. And Farrar permits a court to award no fee at all where only nominal damages are recovered.

Also watch Rule 68. An unaccepted offer of judgment that exceeds the ultimate recovery shifts post-offer costs — and in fee-shifting cases where the statute defines fees as part of costs, it can cut off post-offer fees. Defendants use it deliberately. Evaluate every Rule 68 offer with the fee consequence modeled.

Part 9 — Defending these cases

The sequence: immediate preservation and internal review; watch all the video before adopting any narrative; Rule 12 motion testing the constitutional claim and the Monell allegations; qualified immunity at the earliest defensible point with a stay of discovery; interlocutory appeal from a denial; targeted discovery on damages, prior claims, and credibility; and summary judgment framed on clearly established law.

Evaluate early and honestly. The fee exposure under § 1988 changes the arithmetic completely: a $60,000 verdict can carry a $400,000 fee award, and a case that could have settled for $150,000 in year one can cost $900,000 in year four. Municipal clients should be told this in writing at the outset.

Do not create a spoliation problem. Preserve on notice, suspend auto-deletion, and document the hold. Lost body camera footage in an excessive force case is a case-ending fact regardless of what it would have shown. See Litigation Holds, Spoliation, and Rule 37(e).

Audit before you are asked. A municipality that reviews its own force reporting, complaint dispositions, and early intervention data will find the Monell pattern before a plaintiff does — and can fix it, which is both cheaper and better.

Part 10 — Claim-specific playbooks

The general sequence is the same. What differs is the proof.

Excessive force

Build the timeline in seconds. Synchronize every video source — body cameras from each officer, dash camera, surveillance, bystander phone — against dispatch audio and CAD timestamps. Then chart what each officer could see and hear at each moment. Graham v. Connor is judged from the perspective of a reasonable officer on the scene, so the case is won or lost on what was knowable at each instant.

The questions that decide it: What crime was suspected, and how severe? Was the plaintiff armed, and did the officer have reason to think so? Was the plaintiff actively resisting, passively resisting, or compliant? Was a warning given where feasible — Tennessee v. Garner requires it before deadly force where practicable? How much time elapsed between the threat ceasing and the force continuing? Was the plaintiff restrained when the force was used?

The most productive line in an officer's deposition is not "was this excessive" — an inadmissible legal conclusion — but the granular sequence: "At the moment you delivered the third strike, was Mr. — handcuffed? Was he moving? What did you believe he was going to do?" Answers to those questions, compared against video, decide summary judgment.

False arrest and malicious prosecution

Probable cause is the whole case. Reconstruct exactly what the officer knew at the moment of arrest — not what was learned later. Obtain the arrest report, the affidavit, dispatch records, and any witness statements the officer relied on.

For malicious prosecution, Thompson v. Clark, 596 U.S. 36 (2022), requires only that the prosecution ended without a conviction — a dismissal suffices, without any affirmative indication of innocence. And Chiaverini v. City of Napoleon, 602 U.S. 556 (2024), means that probable cause on one charge does not defeat a claim as to a different charge lacking it — so plead charge by charge.

Watch the accrual rules. False arrest accrues when the plaintiff is held pursuant to legal process; malicious prosecution accrues on favorable termination. Those are different dates and they produce different deadlines in the same case.

First Amendment retaliation

The Nieves problem is that probable cause generally defeats a retaliatory arrest claim. The Gonzalez v. Trevino answer is objective evidence that similarly situated people who did not engage in the protected speech were not arrested — and the Court made clear the comparator showing need not be as exacting as some courts had required.

What to gather: arrest statistics for the same offense in the same jurisdiction; charging decisions in comparable incidents; the officer's own history with similar conduct; and the temporal sequence, especially any statement connecting the speech to the action. Public records requests are usually the best route to the comparator data.

Deliberate indifference to medical needs

Two elements: an objectively serious medical need, and subjective deliberate indifference — more than negligence.

What proves it: the jail's medical intake screening; the sick-call slips the plaintiff submitted and what happened to them; the medical log; the housing and observation records; the contract with the private medical provider and its staffing levels; and the deposition of the officer or nurse who received the complaint. The most powerful document is usually a written request for care with no responsive entry.

Name the private contractor. Correctional medical providers are state actors for § 1983 purposes, they carry insurance, and their contract staffing and cost-containment policies frequently supply the Monell-equivalent theory.

Wrongful conviction

The most complex and most valuable category. The theories are fabrication of evidence, suppression of exculpatory material under Brady, coerced or fabricated witness statements, suggestive identification procedures, and failure to investigate. Prosecutors have absolute immunity for advocacy functions and only qualified immunity for investigative ones, which makes the line between the two the central fight. The claim accrues on vacatur or exoneration, not on arrest — see Heck. These cases take years, require reconstruction of a decades-old investigation, and produce the largest verdicts in the field.

Part 11 — Timeline and cost expectations

Stage	Typical duration	Note
Investigation and pre-suit	1–6 months	Notice of claim may be due in 60–180 days
Complaint to Rule 12 ruling	3–8 months	Qualified immunity often raised here
Interlocutory appeal, if taken	12–24 months	Frequently before any discovery
Fact discovery	8–18 months	Monell discovery dominates
Expert discovery	3–6 months	Police practices, medical, video analysis
Summary judgment	4–9 months	Qualified immunity again
Second interlocutory appeal	12–24 months	If denied again
Trial	1–3 weeks	Bifurcation of Monell is common
Fee petition	3–9 months	Frequently litigated separately

Realistic total: three to six years. Clients must be told this at intake, in writing, along with the fact that qualified immunity may end the case before any discovery occurs.

Costs. Plaintiff-side: police practices expert $15,000–$50,000; video analysis $5,000–$25,000; medical and life care experts $10,000–$60,000; deposition transcripts and records $10,000–$40,000; Monell document review, which can be the largest line of all. Defense-side: hourly defense over four years plus the fee exposure, which is the number that should drive early evaluation.

Part 12 — Ten mistakes that lose civil rights cases

Missing the state notice-of-claim deadline, killing the parallel state claims — including the respondeat superior theory § 1983 does not provide.
Not sending preservation letters within days, and losing body camera footage to a retention schedule.
Group pleading — "Defendants used excessive force" — instead of identifying each officer's conduct.
Pleading Monell in conclusions, producing dismissal before any discovery into the pattern.
Failing to identify controlling clearly established precedent before filing.
Letting a client plead guilty without analyzing the Heck consequence.
Suing the state or a state agency for damages, which Will forecloses.
Accepting a lump-sum settlement inclusive of fees without addressing the conflict and documenting informed consent.
Ignoring a Rule 68 offer's fee consequences, which can cut off post-offer fees entirely.
Keeping poor time records, which converts a strong fee petition into a reduced one.

Part 13 — Frequently asked questions

"Can I sue if I was never charged, or the charges were dropped?" Yes — and it is a better posture, because no Heck bar applies and, after Thompson v. Clark, a dismissal supports a malicious prosecution claim.

"How do I get the body camera video?" Three routes, and use all of them: a preservation letter immediately; a public records request, which many states now specifically address for police recordings; and formal discovery once suit is filed. The first is urgent, the second is free, the third is slow.

"Does the officer's disciplinary history come in?" Discoverable in most circuits as relevant to Monell notice and sometimes to the individual claim; admissibility at trial is a separate question governed by the rules on character evidence and by Fed. R. Evid. 403. Some states have statutes restricting disclosure of police personnel files, and litigating access is frequently a discrete phase of the case.

"Should the Monell claim be bifurcated?" Defendants routinely move to bifurcate and stay Monell discovery pending resolution of the individual claims, arguing efficiency. Plaintiffs resist, because the Monell discovery is the case's value and because bifurcation front-loads the qualified immunity fight. Courts split; the argument is worth making seriously either way.

"What if my client is undocumented, or has a criminal record?" Neither bars the claim. Both will be raised — immigration status is generally inadmissible and its introduction is grounds for a motion in limine; prior convictions are governed by the impeachment rules. Prepare for both in advance rather than at trial.

"Can a family member sue after a death in custody?" Yes, through the state's survival and wrongful death statutes as incorporated by 42 U.S.C. § 1988(a). Who may sue and what damages are available are questions of state law, and they differ enough that the answer must be researched before the complaint is drafted.

"Is a consent decree realistic?" Rarely through private litigation, because of the standing requirements for injunctive relief. Policy change is more often achieved as a negotiated settlement term, which is why it should be raised in mediation rather than pleaded as a demand for an injunction the plaintiff may lack standing to obtain.

Part 14 — Two worked examples

Example A — the case that survives

Facts. Marisol, 44, calls 911 during her adult son's mental health crisis and asks for a crisis intervention team. Two patrol officers arrive. Within four minutes, her son is tased twice, taken to the ground, and restrained prone with pressure on his back for several minutes. He stops breathing and dies.

First week. Counsel sends preservation letters for all video, dispatch audio, taser deployment logs, the CIT dispatch protocol, and the training records for both officers. A public records request seeks the department's policies on prone restraint, excited delirium, and crisis response, plus five years of in-custody death reports. The notice of claim is served on day nine — the state's deadline is ninety days.

Claims. Fourth Amendment excessive force against both officers; deliberate indifference to a serious medical need; a Monell claim on failure to train in crisis intervention and on a custom of prone restraint contrary to national standards; and state-law wrongful death and battery claims.

Qualified immunity. The officers move on the ground that no case addresses these facts. Counsel identifies circuit precedent holding that continued prone restraint of a subdued, non-resisting person violates clearly established law, and argues in the alternative under Taylor v. Riojas that the danger of positional asphyxia was obvious. Denied. Interlocutory appeal adds sixteen months and is affirmed.

The Monell discovery. Training records show the department's crisis intervention training was four hours, delivered once, and that neither officer had attended. The policy warned against prolonged prone restraint; the use-of-force reports show it used in eleven prior incidents with no supervisory correction. Two prior in-custody deaths involved the same restraint. That is notice, pattern, and causation.

Resolution. Settlement of $4.2 million, plus $1.1 million in fees under § 1988, plus binding commitments to a forty-hour crisis intervention curriculum, a prone-restraint prohibition with supervisory review, and annual publication of use-of-force data.

Example B — the case that does not

Facts. Trent is stopped for a broken taillight, argues with the officer, is asked to step out, refuses, is pulled from the car, and is charged with resisting. He pleads guilty to resisting and pays a fine. He then wants to sue for false arrest and excessive force.

The analysis.

False arrest is barred by Heck: a judgment that the arrest lacked probable cause would necessarily imply the invalidity of a resisting conviction that presupposes a lawful arrest.
Excessive force may survive, because force can be excessive even during a lawful arrest — but the resisting conviction narrows the window of force at issue and supplies the defense a strong factual predicate.
The video shows the officer used a control hold and no strikes, and Trent sustained a bruised forearm.
Qualified immunity is likely, because no precedent clearly establishes that a control hold on a refusing subject is excessive.
The notice of claim deadline for state-law claims passed four months ago.
Damages are minimal, and after Farrar even a nominal victory may support no fee.

The right advice is to decline the matter, explain why in writing, and — because this is a real service — explain what could have been different: consulting civil counsel before the plea, serving the notice of claim, and preserving the video. Declining honestly at intake is part of competent practice in this field, and a lawyer who takes every sympathetic case will serve none of them well.

Part 15 — Working with the client

Civil rights clients arrive after something that was, frequently, the worst experience of their lives, and they arrive with expectations shaped by news coverage of the largest verdicts. Managing that honestly is part of the job.

At intake, say these things plainly and put them in writing.

The case may end before any discovery. Qualified immunity can be decided on the pleadings, and a denial can be appealed before the case moves at all. Three to six years is ordinary.
Being right may not be enough. The law requires that the right have been clearly established in a prior case with similar facts. That is not fair in any ordinary sense, and it is the law.
The officer will almost certainly not pay personally. Indemnification is nearly universal. If the client's goal is the officer's financial ruin, this litigation will not provide it.
Discipline and termination are not remedies this case can obtain. Those decisions belong to the employer and, in most jurisdictions, to a civil service or arbitration process.
The client's own history will be examined — criminal record, prior claims, medical and mental health history, social media. Everything. It should be disclosed at intake, not discovered by the defense.
The client will be deposed at length, and the deposition will cover the incident second by second and the client's life broadly.

During the case, the two failures that damage the client relationship are silence and optimism. A quarterly written update, even one reporting that an appeal is pending and nothing will happen for months, prevents most of what goes wrong. And a lawyer who describes each ruling as a step toward a large verdict sets up a settlement conversation that feels like a betrayal.

At settlement, present the arithmetic in writing: gross settlement, fee (whether contingent or statutory), itemized costs, any lien, and net. Explain what the non-monetary terms actually require, and who will enforce them. Where policy relief is part of the settlement, many clients regard it as the most meaningful part of the outcome — say so, and get it in enforceable language rather than in a recital.

And prepare the client for the public dimension. Civil rights cases attract attention. Pleadings are public, depositions may be sought by the press, and a settlement involving public funds is frequently disclosable under state records law. Decide with the client, early, what they want their role in that to be — and remember that a gag provision the client did not want, agreed to in the last hour of mediation, is a term they will regret for years.

Part 16 — The parallel tracks nobody should ignore

A § 1983 case rarely exists alone. Five parallel proceedings frequently run alongside, and each affects the others.

The criminal case. Discussed above, and controlling. Nothing in the civil case should proceed without knowing its posture.

The internal affairs investigation. The agency will conduct one. Its file becomes central discovery. Note that in many jurisdictions officers give compelled statements under a Garrity protection — those statements cannot be used against them criminally but are often discoverable civilly, and the distinction between the compelled statement and the officer's later voluntary testimony is worth understanding.

The administrative or civil service proceeding. Discipline is frequently appealed to a civil service commission or an arbitrator, and a reinstatement decision there has no preclusive effect on the § 1983 case but will be used rhetorically. Obtain the record.

The state tort claim. Different deadline, different immunities, and — critically — often respondeat superior liability against the entity, which § 1983 does not provide. Where the state claim survives, it can be the more valuable theory against the municipality.

A government pattern-or-practice investigation, where one exists. Findings letters, consent decrees, and monitor reports are public, admissible in many circumstances, and provide Monell evidence assembled at public expense. Search for them at the outset.

And in the background, the insurer. Most municipalities carry excess coverage above a self-insured retention or participate in a risk pool. Who actually decides settlement — the city attorney, the risk pool, or the excess carrier — determines who must be in the room at mediation, and identifying that early prevents a mediation attended by someone without authority.

Part 17 — For non-lawyers: what to do if this happened to you

If you believe your rights were violated by police or another government official, the practical steps are short and time-sensitive.

Immediately.

Get medical attention and make sure the record describes what happened and who caused it.
Photograph every injury, that day and again as bruising develops over two weeks.
Write down everything while you remember it: the date, time, location, officers' names and badge numbers, patrol car numbers, what was said, and who was present.
Get the names and phone numbers of witnesses. They disappear.
Note every camera you can see — businesses, doorbells, traffic cameras. Write down the addresses.

Within days.

Talk to a civil rights lawyer. Many will consult at no charge and take viable cases on contingency, because 42 U.S.C. § 1988 allows fees to be recovered from the defendant.
Ask specifically about the notice-of-claim deadline for state claims, which can be as short as sixty days and which nothing else will excuse.
Do not delete anything from your phone or social media.
Request the records yourself if you cannot yet reach a lawyer: file a public records request for the incident report and any video. It is free or nearly free, and video retention schedules are short.

If you were also charged with a crime.

Get a criminal defense lawyer, and tell them you may have a civil claim. A guilty plea can permanently bar part or all of the civil case under Heck. The two lawyers need to talk before any plea.
Do not discuss the incident on a recorded jail phone.

What to expect if you have a case. Years, not months. A fight over qualified immunity that may end the case before anyone examines the facts. A deposition in which your entire history is examined. And, if the case succeeds, most likely a settlement paid by the government rather than by the individual officer. See Facing Criminal Charges and The Criminal Case From Arrest to Appeal.

What you cannot get from this case: the officer fired, criminally charged, or personally bankrupted. Those outcomes belong to other processes. What a successful case can deliver is compensation and, sometimes, a change in the policy that produced the harm — which is not nothing, and is frequently what clients say mattered most.