(CNN) -- A sheriff's deputy who killed six young people at a house party in Crandon, Wisconsin, apparently died after shooting himself three times in the head with a .40-caliber pistol, the state attorney general said.

Tyler Peterson, a sheriff's deputy, shot and killed six people, police said.

Initial reports that 20-year-old Tyler Peterson was killed by a police sniper's bullet were apparently incorrect, though it appears the sniper may have shot Peterson in the arm, Attorney General J.B. Van Hollen said.

Although the final forensic determination could take several weeks, the attorney general said that Peterson had his personal .40-caliber Glock when police found him. The three gunshots to the head came from a .40-caliber.

"The three gunshot wounds to the head included two nonfatal rounds with entry points below the chin, and one fatal shot that entered Peterson through the right side of the head," Van Hollen said.

"Each of the three head shots were fired while the gun was in contact with his skin, or extremely close to the skin," he said. "These three head wounds are consistent with self-inflicted wounds, and not consistent with long-range rifle fire."

The fourth gunshot wound, Van Hollen said, struck Peterson in the left bicep and appeared to have been fired from a rifle "at some distance." Watch Van Hollen explain the shootings "will never make sense" »

Peterson was a Forest County sheriff's deputy and a part-time officer with the Crandon Police Department.

According to Van Hollen, Peterson, while off-duty shortly before 3 a.m. Sunday, entered a house where the seven young men and women had gathered.

While there, Van Hollen said, Peterson apparently got into an argument with Jordanne Murray, accusing her of having a relationship with another person.

"The argument got heated, and Murray demanded he leave," the attorney general said. "Peterson left, and returned minutes later," breaking down the door and opening fire with an AR-15 rifle, of the type he was issued by the Forest County Sheriff's Department.

Police said Peterson fired about 30 rounds.

Fewer than 20 minutes later, a patrolling Crandon police officer, after hearing gunfire, reported it and went to the house to investigate, Van Hollen said.

The officer, Greg Carter, 21, reported seeing Peterson leave the house with a rifle. After momentarily losing sight of Peterson, Carter "heard multiple rounds of gunfire" and his windshield burst.

Peterson escaped. Van Hollen said that Peterson apparently "drove aimlessly around the northern part of the state" for several hours, calling in false reports to police to throw them off.

Peterson ended up at a cabin in the town of Argonne shortly before 8 a.m. He told friends about the shootings, handed over the AR-15 and two other rifles and left the cabin. After meeting with family members, he returned to the cabin around 9:15 a.m.

Police arrived about 15 minutes later, Van Hollen said. Peterson was killed during a police shootout after police couldn't persuade him to surrender.

All seven victims were students or graduates of Crandon High School, from which Peterson also was a graduate.

In addition to Murray, the dead were identified as Aaron Smith, Bradley Schultz, Lindsey Stahl, Lianna Thomas and Katrina McCorkle.

The sole survivor, Charlie Neitzel, 21, "played dead" after Peterson shot him three times, Van Hollen said.

After Peterson shot him once, Neitzel begged him to stop. But Peterson fired again. Neitzel fell to the floor, was shot a third time and didn't move.

"Playing dead until Peterson left, Neitzel survived," Van Hollen said. Neitzel was the last person shot.

Neitzel underwent surgery Tuesday and was in stable condition Tuesday night, a hospital employee said.

The families of the six slain young people asked that media leave them alone in their grief, Van Hollen told reporters.

But the families of the victims also wanted it known that they had met with Peterson's family.

"They hold no animosity toward them," Van Hollen said, conveying the families' wishes that the Peterson family be allowed space and time to heal. E-mail to a friend

All About Shootings • Wisconsin