A man who admitted to the murder of 18-year old Alaskan barista Samantha Koenig was found dead in his jail cell on Sunday of an apparent suicide.

34-year old Israel Keyes confessed not only to Koenig’s murder, he also told investigators he had killed seven others: four in Washington state, two in Vermont, and one in New York. The victims from Vermont were a couple, whose bodies have yet to be found.

The revelation that Keyes seems to have been a serial killer has shaken the town of Anchorage, where he had been jailed for Koenig’s murder, awaiting a March trial. Police say they have been able to corroborate Keyes’ stories about the other victims to the extent that they believe he’s telling the truth.

“Even though Mr. Keyes is now dead, our investigation continues,” said FBI agent Mary Rook.

Keyes had seemingly no motive for the deaths, despite having taken money from the victims; investigators say he asked for ransom money for Koenig well after her death, sending texts from her cell phone and using her bank card to withdraw cash all over the country as he was on the run. Surveillance footage from the coffee stand where Koenig worked showed a man approaching her with a weapon before a struggle ensued, and a white pickup truck was captured on film, but it was too far away to make out details. Narrowing down the circle of suspects, police came across Keyes and eventually got him to talk; he told them he’d cut a hole in the ice of a lake and dropped Koenig’s body into it. Her remains were recovered in April.

As for the other victims, the FBI says they were still working with Keyes to learn about his crimes and say they won’t stop trying to find answers.

“As of this week, we were still obtaining valuable information from Mr. Keyes,” said Kevin Feldis, chief of criminal prosecutions for the U.S. attorney’s office in Anchorage.