The police do not have a right to arrest you unless they have a warrant for your arrest or they have probable cause to believe you have committed a crime. This does not mean that the police must believe beyond a reasonable doubt that you committed a crime; only that it is reasonable to believe that you did. If the police issue a false accusatory instrument against you -- usually a criminal complaint -- then, in addition to falsely arresting you, they have maliciously prosecuted you.
When are you "arrested"?
An arrest occurs when the police stop you and detain you. The police need probable cause even for temporary detentions where you are released before you are taken to the precinct.
You do not Have a False Arrest Claim if the Result of Your Criminal Case Results in a Finding of Guilt
Usually, however, an arrest involves being taken to the precinct, "booked" and then being taken to Central booking to appear before a judge. In order to have a claim for false arrest and malicious prosecution, you must have a "favorable disposition" of your criminal case -- that is, a dismissal. However, we strongly advise you to take the advice of your criminal defense attorney very seriously before deciding not to plead guilty. Your first concern in criminal court must be your criminal case, not preserving a potential future civil case.
Is an Adjournment in Contemplation of Dismissal "ACD" a "Favorable Disposition"
The court may offer you an Adjournment in Contemplation of Dismissal ("ACD"). If you accept it, you are free to go and if you stay out of trouble for 6 months, your case is dismissed and sealed. There is some conflicting law about whether an ACD is a favorable disposition preserving your right to sue for false arrest. However, under federal law, the case survives if you take an ACD, so if you and your criminal defense attorney see an ACD as the best course of action you can accept it without sacrificing your civil case.
Enforce Your Rights: What to do if You are Falsely Arrested
Any identifying information you can gather about the officers who arrested you is helpful, but even if you don't you need not worry because your arrest will likely generate police paperwork. Then file a complaint with your local police review board that has the authority to investigate the incident. Contact a lawyer with the experience and the willingness to take on the police department.