False arrest

False arrest is a common law tort, where a plaintiff alleges he or she was held in custody without probable cause, or without an order issued by a court of competent jurisdiction. Although it is possible to sue law enforcement officials for false arrest, the usual defendants in such cases are private security firms.

After an arrest, if the charges are dropped, a person will sometimes file legal action or a complaint against the appropriate arresting agency. In most jurisdictions, the arrest powers of police and police agents are in excess of those afforded to ordinary citizens (see citizen's arrest). However, the powers of police officers to arrest are not unlimited. Generally speaking:

Most cases of false arrest involve accusations of shoplifting, and are brought against security guards and retail stores. A guard cannot arrest someone merely on the suspicion that person is going to commit a theft. In most jurisdictions, there must be some proof that a criminal act has actually been committed. For example, a guard does not have reasonable and probable cause if a shopper has not yet paid for merchandise they are carrying in the belief that the person intends to leave without making payment. Instead, there must be an actual act committed – the person must make an actual attempt to leave the store without paying for the merchandise.

Note though that some states have enacted "merchandise concealment" laws as a way around this limitation. Under these laws, it is a criminal offense to merely conceal merchandise that has not been paid for, giving stores grounds to make an arrest even if the person has made no attempt to leave the store with the merchandise.

In the United States and other jurisdictions, police officers and other government officials are liable for clear deprivation of rights, but are partially shielded from false arrest lawsuits through the doctrine of qualified immunity, when such a violation qualifies as "not obvious," by a US Supreme Court test. This doctrine can protect officials from liability when engaged in legal grey areas including qualifying discretionary actions in the arrests of suspects. However, the officer's actions must still not violate "clearly established law," or this protection is void. This includes executing an arrest warrant against the wrong person. False statements by public servants to justify or cover up an illegal arrest are another violation of federal law.

...
Wikipedia