FBI investigators now say Keyes also spent a significant amount of time here in the North Country, owning property in Franklin County and disposing of his
murder weapons in St. Lawrence County.
The FBI says Keyes robbed a bank in Tupper Lake in 2009. He also claimed to have brought one of his victims to the North Country, hiding the body here in the region.
She was trying to solve the murder of one woman, Samantha Koenig, who had been abducted from a coffee shop in Anchorage in February — her body later found in a nearby lake.
Goeden says Keyes — who was 34 years old — began dropping clues that Koenig wasn’t his only victim.
"That was a process over time with him during the interviews," she recalls. "We probably met with him over thirty times of the last eight or nine months. He made it pretty clear early on without directly saying it that he was responsible for additional homicides."
Goeden says Keyes was rarely specific or exact. But he offered enough detail that the FBI was able to begin piecing together the scope of his crimes.
"Dropping little hints or little clues. He would provide bits of information about where another victim might be or how he chose victims or where he went to look for victims. It was obvious to us that he had done this before."
This week, the FBI released video tape of Keyes confessing to his method of seeking out victims.
"I would let them come to me just in a remote area, come to a remote area that’s not anywhere near where you live," Keyes said in the video.
"[Locations] that other people go to as well. You might not get exactly...there's not as much to choose from in a manner of speaking. But there's also no witnesses really, there's nobody else around."
As the investigation continued, the FBI called in Vermont officials who were still investigating the disappearance of Bill and Lorraine Currier. The couple vanished from their home in Essex, Vt., in June of last year.
Essex police Lt. George Murtie – speaking at a press conference webcast this week by the Burlington Free Press – said says he became convinced in mid-April that Keyes murdered the Curriers.
He later interviewed Keyes for an hour by telephone. "He went through the details of the crime," Murtie recounted, describing Keyes as "very calm. There was no display of emotion."
While speaking with investigators, Keyes also confessed to robbing several banks – including a robbery in Tupper Lake in 2009.
FBI agent Jolene Goeden says Keyes also claimed to have brought one of his victims to the North Country, apparently concealing the body here.
"It is in northern New York," she confirmed. "We don't have anything specific about where that victim is buried. We have kind of general information, but it isn't specific enough that we're able to recover that victim."
Goeden notes that Keyes owned a 10-acre parcel of land in the town of Constable, in northern Franklin County.
The site was searched in October by FBI investigators based in Albany after local hunters claimed to have seen what looked like grave sites.
"A number of items were seized from that location, but there's no indication at this point based on what Mr. Keyes told us as well as what was uncovered in the search that there is a victim buried on that property," Goeden said.
An FBI dive team did find a pair of pistols and a silencer that Keyes admitted to stashing in a reservoir in Parishville in St. Lawrence County – the same weapons used in the murder of the Curriers in Vermont.
FBI officials say Keyes threatened to stop talking if his crimes were revealed to the media.
Details were only released this week after Keyes killed himself on Sunday, cutting his wrist with a disposable razor and choking himself with bedding material.
The fact that Keyes was allowed to commit suicide while in custody has sparked a separate investigation.
In an interview with KSKA public radio in Anchorage, Alaska Department of Corrections spokesman Brian Brandenburg acknowledged that safeguards were supposed to be in place.
"In Mr. Keyes case, he actually was in segregation. Typically most high profile cases, those folks are kept segregated from general [inmate] population."
Brandenburg says there was no indication that Keyes planned to do himself harm. The killer apparently wasn’t under the care of psychiatric staff.
But FBI agent Jolene Goeden says Keyes suicide will make it far more difficult for them to uncover details of his murders and the location of his victims.
"I think we still have a lot of work ahead of us," Goeden said. "This case is a little different from other serial killer cases, where typically you would find a number of victims and try to connect them back to a person. In this case, we have the person and we're trying to find the victims."
The FBI is building a timeline of Keyes travels and activities, both here in the North Country and in other parts of the US – hoping to discover whether he’s connected to other missing person cases.
It appears highly unlikely that Keyes was involved in the high profile disappearance of Colin Gillis, a Tupper Lake man who vanished in March of this year and whose case remains unsolved.
According to records of Keyes’ travels, the serial killer was in the Southwestern US when Gillis went missing.
Keyes was arrested in Texas two days after Gillis was last seen here in the North Country.
Click here to find Martha Foley's conversation with Brian Mann on the Israel Keyes investigation.