Further developments include a list released by the FBI that detail 35 trips Keyes made around the U.S., Mexico and Canada over the last eight years.
Keyes was the suspect in the Samantha Koenig murder case, as well as the possible suspect in other slayings around the country. He was found dead in his jail cell Sunday of an apparent suicide.
The 34-year-old alleged murderer was set to go on trial in March for the murder of Koenig, an 18-year-old barista from Anchorage who went missing last February. Police said Keyes confessed to killing Koenig after he was arrested in Texas using her debit card as well as confessed to the killings of others around the country. Keyes faced the death penalty in the Koenig case.
Authorities are now in the process of conducting an investigation which will explore the possibility that Keyes traveled to kill simply because he "liked to do it," prosecutors said.
"In a series of interviews with law enforcement, Keyes described significant planning and preparation for his murders, reflecting a meticulous and organized approach to the crimes," the Anchorage FBI office said in a statement obtained by ABC News.
The news network has obtained a timeline of Keyes' travels that reportedly showed nearly three-dozen trips between 2004 and 2012.
While the destinations on the timeline are vague, the FBI, which released the timelines, said that they span he entire country, including Hawaii. There are also trips to Canada and Mexico listed, ABC News reports.
"Keyes also admitted traveling to various locations to leave supplies he planned to use in a future crime. Keyes buried caches throughout the United States," the FBI said.
Reports indicate that the FBI has already recovered two “caches,” one in Alaska and one in New York. Both reportedly contained money, weapons and items for disposing of bodies. Keyes indicated that there were other supply boxes buried across the country.
Anchorage police chief Mark Mew told CBS Keyes admitted to killing Bill and Lorraine Currier of Essex, Vt. in June 2011, as well as four other victims whom he did not name in Washington state and another in New York.
"Investigators believe that Keyes did not know any of his victims prior to their abductions," the FBI told reporters. "He described several remote locations that he frequented to look for victims--parks, campgrounds, trailheads, cemeteries, boating areas, etc."
Samantha Koenig went missing on Feb. 1 and was last seen on footage from a surveillance camera being forced away from the coffee shop she worked at with an armed man alleged to be Keyes.
The FBI said Keyes killed Koenig a day after she was kidnapped. Her body was found April 2 in an icy lake north of Anchorage. Koenig's family said there was no connection between the 18-year-old and Keyes prior to the murder.
Keyes was eventually found after stealing Koenig's debit card from her car and making withdrawals from automated teller machines in Alaska, Arizona, New Mexico and Texas. Keyes also used her phone to send texts to hide her death, one of which included the demand for a ransom. He arrested in Texas charged with kidnapping resulting in the death of Samantha Koenig.