Investigators learned that Israel Keyes, 34, hid one weapons cache in Eagle River, Alaska, and buried another containing items to get rid of bodies near a popular fishing spot in New York, the Anchorage Daily News reported Tuesday.
Keyes was in jail for the February kidnapping and killing of Samantha Koenig, 18, of Anchorage, when he was found dead in his cell Sunday apparently after taking his own life.
During his incarceration, he confessed to killing Koenig and William and Lorraine Currier of Essex, Vt., Alaskan authorities said.
The U.S. Army veteran and self-employed carpenter also admitted to five additional killings and suggested there were others.
Among those he told investigators about were a couple from Washington state, two unrelated people from Washington state and an individual whose body was disposed of in New York state, the FBI said.
Keyes said he would fly to a city, rent a car and drive hundreds of miles away to kill or rob banks.
Chief criminal prosecutor Kevin Fields of the U.S. Attorney's Office in Anchorage said the way Keyes traveled and moved around allowed him to remain undetected for more than a decade.
Investigators were in the process of getting more information about his alleged victims when he took his own life.