Here is the most recent news update from the Valley Morning Star:

CRANDON, Wis. (AP) -- A young sheriff's deputy who opened fire on a pizza party and killed six people reportedly flew into a rage when he was rebuffed by his old girlfriend, and others at the gathering called him a "worthless pig."

A longtime friend told the Milwaukee Journal Sentinel on Monday that 20-year-old Tyler Peterson came to his door in the hours after the rampage and calmly explained what he had done.

"He wasn't running around crazy or anything. He was very, very sorry for what he did," Mike Kegley told the newspaper, adding that he gave Peterson coffee and food and later called 911.

Peterson told Kegley that he had gone to his ex-girlfriend's house early Sunday morning in hopes of patching up the relationship after a recent breakup. But, he said, Peterson lost control when the meeting ended in an argument and other people started ridiculing him as a "worthless pig."

Police, who declined to provide details of the argument, said Peterson stormed out, retrieved an AR-15 rifle from his car outside and burst back into the house firing 30 shots that killed all but one of the people at the party.

Peterson, a deputy and part-time police officer, later died after exchanging gunfire with law enforcement officers. Whether Peterson was shot by police or took his own life was unclear.