(ANCHORAGE, Alaska) -- A man charged in the death of a teenage barista in Alaska told police that he traveled the country with the sole purpose to kill strangers because he "liked to do it," prosecutors said Monday.
Vermont and federal prosecutors detailed the meticulous and cold-blooded murder of Bill and Lorraine Currier in Essex, Vt., last year and said the information came from Israel Keyes before he killed himself in an Alaska jail cell Sunday. Keyes provided details that only the perpetrator would know, police said.
Keyes, 34, the owner of an Anchorage construction company, was in jail charged with the February murder of Samantha Koenig, 18. While in jail he had been confessing to at least seven other killings in Washington, New York, and Vermont.
Now that he is dead, investigators are wondering how many more killings Keyes might be responsible for and why he committed the crimes.
"He provided some motivation, but I don't think it's really [possible] to pigeonhole why he did this," Tristram Coffin, U.S. Attorney in Vermont, said at a news conference Monday. "He described to investigators that this was a volitional act of his. He wasn't compelled by some uncontrollable force, but it was something that he could control and he liked to do it. Why someone likes to act like that, nobody knows."
Authorities described the murders of the Curriers in great detail, offering insight into how the twisted killer traveled to murder, his criteria for choosing random victims and his careful planning of the murders.
"When [Keyes] left Alaska, he left with the specific purpose of kidnapping and murdering someone," Chittenden County State Attorney T. J. Donovan said at the press conference. "He was specifically looking for a house that had an attached garage, no car in the driveway, no children, no dog."
The Curriers, unfortunately, fit all of Keyes' criteria. He spent three days in Vermont before striking. He even took out a three-day fishing license and fished before the slayings.
In June 2011, Keyes went to their house and cut a phone line from outside and made sure they did not have a security system that would alert police. He donned a head lamp and broke into their house with a gun and silencer that he had brought with him.
Keyes found the couple in bed and tied them up with zip ties. He took Lorraine Currier's purse and wallet as well as Bill Currier's gun. He left the man's wallet.
He put the couple in their own car and drove them to an abandoned farmhouse that he had previously scoped out. Keyes tied Bill Currier to a stool in the basement and went back to the car for Lorraine Currier.
"Keyes saw that Lorraine had broken free from the zip ties and observed that she was running towards Main Street," Donovan said. "He tackled her to regain control of her."
Keyes took Lorraine Currier to the second floor of the farmhouse and tied her up. He rushed to the basement when he heard commotion and found that Bill Currier's stool had broken and he was partially free.
"In an attempt to subdue Bill Currier, Keyes hit him with a shovel, but he continued to struggle and yell wanting to know where his wife was," Donovan said. When Keyes was unable to subdue Bill Currier, he shot him to death, the state attorney said.
"They fought to the end," a choked up Donovan said at the news conference.
Keyes then returned to Lorraine Currier and sexually assaulted her before strangling her. He put each of his victims in garbage bags, put them in the corner of the farmhouse and covered them in debris.
Keyes drove away with the intention of robbing a bank, but had some trouble with the Curriers' car, so he abandoned it and drove his rental car to Maine. Shortly after, he stopped at a national forest to burn the couple's property and then went back to Vermont to visit the crime scenes.
He disposed of the two guns and a silencer in a reservoir and began to make his way back to Alaska.
"By all accounts, [the Curriers] were friendly, peaceful, good people who encountered a force of pure evil acting at random," an investigator said at Monday's news conference. Authorities called the ongoing investigation a "huge case, national in scope."
Before his death, Keyes indicated that he also killed four people in Washington State and one person in New York, but did not give the victims' names, authorities said.
Keyes had been facing a March trial in Anchorage federal court -- and possibly the death penalty -- for the killing of Koenig.
Samantha Koenig was last seen Feb. 1 on surveillance video that showed her leaving the Common Grounds Espresso stand in Anchorage with an armed man. All of the coffee stand's cash was also missing.
After allegedly killing Koenig, Keyes used her phone to send text messages to conceal the abduction, according to prosecutors. He flew to Texas and returned Feb. 17 to Anchorage, where he sent another text message demanding ransom and directing it to the account connected to the stolen debit card, according to prosecutors.
Keyes was arrested in Lufkin, Texas, March 16 after he used Koenig's debit card. The FBI contends Keyes killed Koenig less than a day after she was kidnapped. Her body was recovered April 2 from an ice-covered lake north of Anchorage.
Police and the FBI spent hours talking to Keyes in the months after his arrest and he was cooperating, talking to investigators as recently as Thursday, the Anchorage Daily News reported.
Authorities wouldn't say how Keyes killed himself, only that he was alone in his cell. An autopsy will be conducted.
Alaskan officials were expected to release a timeline of Keyes' U.S. travels Monday.
Copyright 2012 ABC News Radio