If you see a crime happening, call 9-1-1 (if it is urgent) or call your local police.
If it is safe and you are not threatened, wait for the police to come. As a witness, it is your duty to talk to the police. The police will talk to you and other witnesses. Speaking with witnesses helps the police gather evidence to be able to arrest a criminal. If a witness cannot speak English, the police will get an interpreter. Witnesses provide their name, address, phone number, and describe the crime they witnessed.