AP NewsBreak: FBI says Alaska man killed for fun

Israel Keyes confessed to killing eight people across the country before he committed suicide last weekend in an Anchorage jail, but FBI and Anchorage police investigators said Friday they think he may have had up to three additional victims.

"Based on some of the things he told us, and some of the conversations we had with him, we believe the number is less than 12," FBI Special Agent Jolene Goeden said. "We don't know for sure. He's the only one who could have ultimately answered that."

Keyes slit his wrist and strangled himself with bedding Sunday at the Anchorage Correctional Facility. He was facing federal murder charges in the kidnapping and death of an 18-year-old Samantha Koenig, who was abducted from an Anchorage coffee stand Feb. 1.

Goeden and Anchorage Police officer Jeff Bell conducted up to 40 hours of interviews with Keyes after his March arrest in Texas. During that time, Keyes confessed to killing Koenig, along with Bill and Lorraine Currier in Vermont, and five other people — although details for those victims were scarce.

The interviews also revealed Keyes' motivation, which was simple, Goeden and Bell told The Associated Press.

"He enjoyed it. He liked what he was doing," Goeden said. "He talked about getting a rush out of it, the adrenalin, the excitement out of it."

Keyes also liked seeing coverage of his crimes in the media, and he appeared to get a thrill out of talking about some of them with investigators, Goeden and Bell said.

His crimes started small with burglaries and thefts — until the urge escalated to murder.

Bell said Keyes told investigators the first violent crime he committed was a sexual assault in Oregon, in which he let the victim go.

"He planned on killing her but didn't," Bell said.

Keyes said the rape occurred sometime between 1996 and 1998 along the Deshutes River near Maupin, Ore., after he got the girl away from her friends. The girl was between the ages of 14 and 18, and would be in her late 20s or 30s now. No police reports were filed, and the FBI is seeking more information on the crime.

Of the five other murders Keyes confessed to, four were in Washington state and one occurred on the East Coast, with the body disposed of in New York.

In the case of the Curriers, authorities say Keyes flew from Alaska to Chicago on June 2, 2011, rented a car and drove almost 1,000 miles to Essex, Vt.

There, he carried out a "blitz" style attack on the Curriers' home, bound the couple and took them to an abandoned house. Bill Currier was shot, and his wife was sexually assaulted and strangled.