Serial killer found dead in Alaska jail cell, officials say FBI officials say they believe Israel Keyes was a serial killer. He had confessed to eight murders. ANCHORAGE, Alaska -- A confessed serial killer awaiting trial for the kidnapping death of an Anchorage teenager was found dead in his jail cell Sunday in an apparent suicide, law enforcement officials said. Israel Keyes had admitted to abducting and killing 18-year-old Samantha Koenig, who disappeared in February from an espresso stand in Anchorage, officials said at a news conference Sunday. Keyes also admitted to killing a Vermont couple, Bill and Lorraine Currier, in June 2011, and up to five more people whom he did not name, prosecutors said. Keyes revealed his past crimes in dozens of hours of interviews conducted after he was arrested for Koenig's death, officials said. "He did tell us that he had killed other people and that there were bodies of up to four other people in Washington state, as well as a body disposed of in New York state," Assistant U.S. Attorney Kevin Feldis said after the press conference. There may be even more murder victims, Feldis said. Keyes also admitted to two bank robberies, one of them committed in Texas after Koenig's murder, Feldis said. FBI officials said they considered Keyes to be a serial killer, NBC station KTUU reported. We've developed information that he was responsible for multiple additional victims. To our knowledge there are no other victims here in Alaska. They're all in the Lower 48," FBI Special Agent Mary Rook told the station. We do know he traveled extensively and he didn't always stay where he landed. He would land in one airport, rent a car and drive hundreds of miles," she added. Alaska barista Samantha Koenig, 18, was abducted after she closed up a coffee stand in Anchorage. Father of abducted barista, 18, pleads for her return The FBI told the station that it had spoken with its behavioral analysts in Quantico, Virginia, to get insight into Keyes" personality. "He was very, very sensitive to his reputation," Anchorage Police Chief Mark Mew said, according to KTUU. As odd as that sounds, we had to keep things extremely quiet in order to keep him talking with us. Details about the cause of Keyes' death were not released, but a spokeswoman for the Alaska State Troopers said he was alone in his cell and that foul play was not suspected. Texas arrest in case of abducted 18-year-old Alaska barista Sunday's news conference was the first public release of many details about a case that has transfixed Anchorage residents. Koenig's disappearance from the coffee stand in February triggered a city-wide search and a reward fund. Keyes was arrested in Texas after using a debit card linked to Koenig. Investigators found Koenig's body in early April in an iced-over lake north of Anchorage. Officials said Sunday that Keyes' initial confession led them to that location, and that he had admitted using a chainsaw to cut a hole in the ice to dump her body in the lake. Body in icy lake is missing Alaska barista, police say Koenig's body is the only one of Keyes' victims that has been found, officials said Sunday. Although Keyes told investigators that he placed the Curriers' bodies in an abandoned Vermont house, that house was demolished and searchers were unable to find the victims' remains at the site, officials said. Law enforcement officials described Keyes as methodical and a frequent traveler, able to conceal his actions and dispose of his victims' bodies without easy discovery. Keyes, 34, was a self-employed carpenter and Army veteran who had been stationed at Fort Lewis in Washington state. He moved to Anchorage in 2007. He also had a house and property in Constable, New York. He had been scheduled for trial in March on federal charges, and faced a possible death penalty. The investigation into Keyes' crimes - some of which date back 14 years - will continue, a process that could take years, officials said. "Mr. Keyes never showed no remorse for his actions," Feldis told KTUU. Michelle Tasker, a spokeswoman for the Koenig family, told KTUU Sunday that news of Keyes' apparent suicide was not the outcome they wanted. "We would've obviously liked for him to have gone in front of a jury of his peers and answer for what he's been accused of doing," said Tasker. He did an injustice again to Samantha. Reuters contributed to this report.