But two months after the sheriff's deputy killed six people in a Crandon apartment, the details of the rest of his final hours are much less certain.
The state Department of Justice has refused to release any witness statements or reports generated by law enforcement agents investigating the massacre and the subsequent search for Peterson. In a response to open records requests submitted by the Journal Sentinel, the department's records custodian wrote that releasing the reports would interfere with the continuing investigation.
Forest County District Attorney Leon Stenz has said he is awaiting the state's full report on that investigation - including full autopsy reports, which have not been completed.
The Forest County Sheriff's Department has denied a request for the recordings of all calls made to the department over the weekend of Oct. 6 and 7, as well as requests for its policies regarding its Special Emergency Response Team and the allocation of the AR-15 rifles.
The Crandon Police Department might or might not have documents that would fill in some blanks. The Journal Sentinel was told that reports and investigative materials related to the case were mailed last week, but so far nothing has arrived.
The refusal to release any investigative findings leaves a host of questions, even though Peterson acted alone and is dead.
Could authorities have nabbed Peterson when he left his friend's cabin about 8:30 a.m. Oct. 7, drove to talk to his mother and then returned 45 minutes later? Could the friends have left the cabin, allowing authorities to move in without fear that anyone could be hurt? Could the off-duty officer have been coaxed into surrendering?
These and numerous other questions about Peterson, his crimes and the hours he spent holed up at a friend's cabin about five miles north of town remain unanswered. Even if the law enforcement agencies eventually open their records, they might not shed light on some of the communication because the volume of calls overwhelmed the county emergency system and much was communicated by cell phone, with no recordings.
Peterson, 20, shot and killed his former girlfriend, Jordanne Murray, 18, and five other young men and women in the early Sunday morning hours of Oct. 7. He wounded Charlie Neitzel, a 21-year-old who still is recovering.
After the shootings, Peterson headed to the home of Mike and Mary Kegley.
Hours later, the situation on Kegley's land reached its desperate conclusion, with snipers deployed in the woods under orders not to allow him to escape at the tree line, roughly 50 yards away.
"We told him, 'If you make an attempt to go to the woods, we will take you down,' " Forest County Sheriff Keith Van Cleve recounted last week in his first public comments.
According to Wisconsin Attorney General J.B. Van Hollen, Peterson committed suicide with his handgun.
"We gave Tyler every opportunity to give up and come in," Van Cleve said. "He knew what he did, and he didn't want to go to prison. After killing six people, he knew he wasn't going to get out."
What happened in between those bookend events - the apartment massacre and the death of Peterson - is what remains unsettled.
Mike Kegley is one of many people replaying the timeline with skepticism about how law enforcement responded.
According to Kegley, his wife first called the sheriff's department shortly before 8 o'clock that Sunday morning. Peterson later left the property to meet his mother and grandmother on a nearby highway, then returned.
Van Cleve last week confirmed Mary Kegley made the first call about 8 a.m., but he added the call was not recorded. He also said by the time the call came in, Peterson already had left to meet his family, and authorities doubted he would return. At that point, dozens of deputies and police officers were furiously expanding their search in response to other tips placing him in other counties.
Once Peterson returned to the cabin, the Kegleys said, they placed dozens of calls to the Forest County Sheriff's Department.
But only three turned up on the dispatch tapes made that morning, according to the limited records that have been produced by authorities.
Van Cleve said last week that the Special Emergency Response Team was in place after the first call, though out of the Kegley's view, around their property 10 minutes later.
"The Kegleys don't think there was a response, but there was an immediate response," the sheriff said. "It's stupid to say that we had Tyler located, and we didn't respond."
More than three hours ultimately elapsed before the final confrontation, and the Kegleys have asked why no one moved to apprehend Peterson during that time. At one point, others at the cabin called to tell police that Peterson had gone to sleep in his pickup truck.
Van Cleve said authorities couldn't be certain that Peterson was sleeping, and authorities feared for the safety of those near him.
"The Kegleys hindered the operation more than they helped," Van Cleve said. "They made themselves hostages. I think they thought they were being goody two-shoes and were going to talk the guy out. They should have gotten the hell out of there and let us do our job, and it would have gone much smoother."
In earlier interviews, the Kegleys said they left the property about 10:30 a.m. to look for the police. They found them, down the road from their house. But their son, Matt, refused to leave his friend.
The Kegleys contend they were never asked to leave.
"Why in the heck didn't they tell us to get the hell out of there instead of saying, 'Go back in there and do what you can,' do their job for them," Mike Kegley said in an interview last week. "All (Crandon Police Chief John Dennee) said was, 'Be careful.'
" While at the Kegley's, Peterson made at least two calls to the Forest County sheriff and talked with Dennee and others. Those calls were not recorded, according to Van Cleve. They also were not fruitful.
"We weren't getting anywhere," Van Cleve said. "He had two choices: to give up or to go out the way he did, and he chose the latter of the two."
From the Dec. 9, 2007 editions of the Milwaukee Journal Sentinel