Citizens have fairly broad arrest powers here in Alaska:

"AK Stat § 12.25.030

(a) A private person or a peace officer without a warrant may arrest a person

(1) for a crime committed or attempted in the presence of the person making the arrest;

(2) when the person has committed a felony, although not in the presence of the person making the arrest;

(3) when a felony has in fact been committed, and the person making the arrest has reasonable cause for believing the person to have committed it."

What are they like where you live?