PatrolSync

A peace officer may arrest a person without a warrant when: the officer has probable cause to believe the person committed a public offense in the officer's presence; the person has committed a felony, even if not in the officer's presence; or the officer has probable cause to believe the person committed a felony.

Additional mandatory-arrest provisions apply to domestic violence and protective-order violations - see full statute for those subsections.

A private person may arrest another: for a public offense committed or attempted in their presence; when the person arrested has committed a felony, although not in their presence; or when a felony has in fact been committed and they have reasonable cause to believe the person arrested committed it.

Enacted 1872, text unchanged since.

A peace officer may use objectively reasonable force to make an arrest, prevent escape, or overcome resistance. Deadly force is justified only when the officer reasonably believes, based on the totality of the circumstances, that it's necessary to defend against an imminent threat of death or serious bodily injury to the officer or another person, or to apprehend a fleeing person for a felony that threatened or resulted in death or serious bodily injury if the officer reasonably believes that person will otherwise cause death or serious injury.

This is a paraphrase of a legally significant and frequently-amended section. Confirm current statutory text at leginfo.legislature.ca.gov and always follow your agency's use-of-force policy, which may be more restrictive than state law.