CRANDON, Wis. -- A small northern Wisconsin community is dealing with the murderous rampage of an off-duty sheriff's deputy and the focus of the national media.

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Authorities said that Tyler Peterson, 20, fatally shot six young people in Crandon and critically injured another on Sunday. After a manhunt, Peterson was found dead hours later in a house in Argonne, north of Crandon. It's unclear if he shot himself or was shot by police.

Crandon Mayor Gary Bradley said late Sunday afternoon it was his understanding that Peterson was killed by police in the melee.

"He was brought down by a sniper," Bradley said.

The young people had gathered for pizza and movies on homecoming weekend.

Authorities said that Peterson, an off-duty Forest County sheriff's deputy and a part-time Crandon police officer, apparently entered the home and opened fire. The motive is unclear, but the mother of one victim said that Petersen might have been a jealous boyfriend.

The lone survivor of the spree was in critical condition on Monday morning, but was later upgraded to serious condition. Charlie Neitzel, 21, of Pickerel, is being cared for at St. Joseph's Hospital in Marshfield.

Three of the victims were Crandon High School students and the other three were recent graduates. The Crandon School District has called off classes today.

Rose Gerow is the aunt of Bradley Schultz, another young person who died in the shooting. She said that the crime is so senseless because they were friends. Peterson attended high school with them.

In a community of 2,000, no one has gone untouched by the tragic events. Crandon is about two hours north of Green Bay. It's in an area known for logging, and fishing, hunting and snowmobiling. It's also home to the World Championship Off-Road Races.

Mayor Gary Bradley said that his community needs support and he's not yet sure how to put it all back together.

Shooter's Father Talks About His Family

Peterson's father, Steve Peterson, said that nothing the family can say about his son now would be believable to most people.

Relatives said that one of the victims had a romantic relationship with Peterson and recently broke up with him.

The family shared their sorrow over the loss of so many young lives through a statement read at a news conference on Monday afternoon.

The Petersons told the victims' families that they feel a tremendous amount of guilt and shame for the horrible act Tyler had committed.

The Petersons said they were struggling to understand why Tyler did such a thing, but may never have the answers.

The family expressed shock and disbelief and said they are grieving for the losses.