CRANDON, Wis. -- Wisconsin Attorney General J.B. Van Hollen said on Monday that Forest County Sheriff's Deputy Tyler Peterson retrieved a rifle from his truck, then forced his way into a Crandon duplex and fired 30 rounds, killing six and injuring one during a weekend shooting rampage.

Van Hollen said that evidence from multiple sources shows Peterson was the only perpetrator in the shooting. He said that Peterson had been to the apartment earlier and had an argument.

Law enforcement said that Peterson had dated one of the victims on and off.

Van Hollen said that after Peterson left the apartment, he fired numerous rounds at a responding Crandon police officer. That officer was injured by flying glass.

He said that after Peterson fled, he spoke with the Crandon police chief by phone and confirmed to the chief that he was the shooter.

Peterson was located in a residence in Argonne hours later and exchanged shots with law enforcement officers. The attorney general said that the cause of Peterson's death is still under investigation.

Forest County District Attorney Leon Stenz said that he tried to negotiate with Peterson by phone to get him to surrender.