This month, the FBI made public more information about the serial killer Israel Keyes, whose murder spree included time in the North Country and Vermont. Authorities believe that Keyes' murder spree continued for more than a decade and left as many as 11 people dead before he was captured in March of 2012.

Keyes committed suicide in a jail cell in Alaska last December, leaving unanswered questions about most of his victims.

For the first time, the FBI has released hours of video tape from their interviews with Keyes. The video offers a terrifying portrait of a killer who felt no remorse, who at times seemed to be taunting investigators.

If I'm dead, the investigation from the Federal government's point of view is pretty much closed. - Israel Keyes

We’ve known from the start that Israel Keyes was a frightening man, a skilled and cautious predator who sought victims in campgrounds and out of the way places.

He told FBI investigators right up front that he would be elusive, even when held in shackles and trapped in a jail cell.

"There is no one who knows me or who has ever known me who knows anything about me really," Keyes claimed. "I'm two different people basically."

When asked how long he had lived his double life, Keyes laughed and said, "Long time. Fourteen years."

The video released this month by the FBI shows that Keyes remained as secretive in captivity as he was during his long murder spree.

Again and again, the video shows investigators trying to pin Keyes down, trying to tease out new bits of information about his crimes and his victims.

The FBI questioned Keyes about his time in Franklin County, where he owned land in the town of Constable.

"I was there just a year or so ago," he acknowledged, but he declined to offer specifics.

During interviews that continued for more than half a year, the FBI knew that it had Keyes dead to rights on at least a handful of crimes – including the death of a coffee shop worker in Alaska.

But Keyes continued to hint at other murders, suggesting that he had killed as many as 11 people – including a victim in New York.

He suggested that he had buried a body somewhere Upstate and talked about his killing spree without any sense of remorse.

When describing his murder of Bill and Elaine Currier in Essex Vermont in 2011, he actually joked about the crime.

Keyes said he “almost felt guilty” for revealing the rough location of the bodies – because the effort to find remains was costing so much money. "I should have kept my mouth shut," he joked.

At times during the interview sessions, Keyes seems to be playing with investigators.

Late in 2012, investigators had arranged for him to talk by satellite link with an FBI team on the ground in Tupper Lake, where Keyes robbed a bank. But Keyes refused at the last minute to take part.

"Oops," Keyes said, before bursting out in laughter.

During a court hearing in May of 2012, Keyes tried to escape, sparking a rare show of anger from FBI investigators conducting the interviews.

But Keyes again showed no remorse.

"Come one, let's face it. I'm a bad guy who tried to escape, but nobody really thought I was a good guy before that."

FBI investigators tried to play on Keyes’ one central demand – that his murder spree be kept out of the press, out of the media, as much as possible.

Keyes said he hoped that his young daughter would be spared as many of the details of this crimes as possible.

"A really big concern to me is that my kid is going to be around. I don't want her to type my name into the computer and have [my crimes] pop up."

FBI officials agreed to slow efforts to prosecute Keyes in the state of Vermont, to minimize the amount of media attention his case would draw.

But Keyes ultimately offered very little information in return and continued to hint that he would take his own life.

"If I'm dead, the investigation from the Federal government's point of view is pretty much closed," he said.

By late November of last year, during their final interview, Keyes seemed more detached. "I’m losing interest in the legal process," he said.

When the FBI threatened him with a high-profile prosecution in the state of Vermont, Keyes was unmoved.

"The problem is, I don't have any typical demands. There's not anything you can offer me at this point and I realize that now."

On December 2nd 2012, Keyes was found dead in his jail cell in Anchorage Alaska. He left a suicide note but once again offered no clues about his victims, their names or the location of their bodies.