An ex-Marine acquitted on charges of killing unarmed Iraqi detainees has sued a Southern California city over not being rehired as a police officer.

Jose Luis Nazario filed the lawsuit Wednesday in U.S. District Court, seeking more than $4.5 million in damages.

Nazario's attorney Joseph Preis claims the city of Riverside violated a federal employment law that prohibits discrimination against veterans.

A phone message left for the Riverside city attorney wasn't immediately returned.

Nazario was acquitted of voluntary manslaughter in 2008 after authorities alleged he killed or caused others to kill four unarmed detainees in Fallujah, Iraq, in 2004.

Nazario was fired by Riverside officials shortly before his arrest in 2007. He claims the city said it would rehire him if he was acquitted.