'Judgment Ridge'

In January of 2001, beloved Dartmouth University professors Half and Susanne Zantop were found murdered in their home in Etna, N.H. They were victims of two high school students looking only for someone to rob and kill.

The Boston Globe reporters Dick Lehr and Mitchell Zuckoff covered the murder trial and have written a book about the case called "Judgment Ridge."

The murders were a true mystery; the Zantops seemingly had no enemies. Both were highly regarded, much-loved professors

Zuckoff tells The Early Show co-anchor Rene Syler, "It was a murder without motive. Didn't make sense. America was sort of trying to figure out why would these people be killed and then even when they arrested these two boys, still, why would kids looking for robbery end up with a butchery like this?"

The case got international attention, but right before the trial, Zuckoff notes, the boys pled guilty. Lehr adds, "In a sense, America was denied a trial at which we might have gotten some understanding about what happened here and that's what we do in the book is, write about the case and what happened."

The killers were two high school teenagers, Robert Tulloch and Jim Parker. Tulloch, a little bit older than Parker, was the leader, Lehr explains.

"The main thing that we uncovered," he says, "is that what makes this thing happen is that Tulloch is a budding psychopath, serial killer in the making. And that's the core and conclusion we come to after studying this case for years."

Zuckoff says they came up to that conclusion partly because of Tulloch's appearances in court, in which he seemed to be lacking emotion. He adds, "We spent two years investigating the story and looking into literally thousands of pages of documents, his own writings. All these different little pieces started to fit. And the psychopath checklist, he fits it to a tee. It's the only thing that could explain how he could pull in his younger friend, how he could sort of create this world where it made sense in some bizarre way to kill the professors."

Lehr notes, "A lot of what the boys were up to, planning an adventure and escape from a small town, rebeling, wanting to be self-reliant, those are stuff the teens do, part of the typical teen experience, in a way."

What leads to murder is putting a budding psychopath into the mix, Lehr adds.

Zuckoff retells the events of that tragic night of Jan. 27, 2001: "A woman came to the Zantops door for a dinner party. Knocked on the door, didn't hear an answer. She comes in and sees her best friends lying dead on the floor of their study. They had been butchered. No clues but the police found two knife sheaths that ultimately led across the border of Vermont, across Judgment Ridge, to Robert and Jim."

Lehr adds, "One of the horrible ironies of this case, what makes it so tragic is that Half Zantop opened the door to two boys who posed as students doing a survey. A professor at Dartmouth, he let them into his home, which is what he was put on Earth to do, which was to teach and help. And he was butchered for it."

The authors note in the book that the Zantops were just random victims.

Zuckoff says, "Robert Tulloch wanted to get a few kills under his belt is what he later said." Lehr adds, "That is a comment he later made in prison."

Zuckoff says, "If he hadn't been stopped here, we're certain he would have gone on to Ted Bundy, Jeffrey Dahmer status as blood killers."

The blood bath in the Zantops home puzzled investigators for weeks, Lehr says.

"Investigators were stymied for weeks and that was part of the national interest and concern in it. What the heck happened here? Who did it? When the trail led to this wonderful little town in Vermont - Chelsea, Vt. - it only heightened the mystery. These two seemingly normal boys were the prime suspects."

Zuckoff notes they wouldn't have written the book if they had not felt they had gotten to the bottom of the case. He says, "We knew as journalists and as parents this was a deeply troubling case involving two seemingly normal boys. We wanted to know what happened here, I think, like a lot of other people did."