By Alex Tresniowski
April 22, 2002 12:00 PM

Why would anyone do this? For months the question tormented friends and relatives of Half and Susanne Zantop, the vibrant and much-loved Dartmouth professors who were knifed to death in their New Hampshire home on Jan. 27, 2001. Who would target two such gentle souls for murder?

It turns out that the Zantops were random victims, chosen to die that day by chance. But now that the Dartmouth double-murder case has been abruptly closed with the surprise guilty plea of Robert Tulloch, 18—and with the dramatic sentencing of Tulloch and his high school pal and accomplice James Parker, 17, on April 4—troubling questions remain. What would lead two such bright kids with no history of violent behavior to commit such a horrible crime?

The answer is shockingly prosaic. Prosecutors disclosed that the teens killed the Zantops because they had become bored with their lives in quiet Chelsea, Vt. “They wanted to go to Australia, and they began plotting ways to obtain enough money to support their trip,” New Hampshire Assistant Attorney General Kelly Ayotte told the court on April 4. “They came up with a goal of $10,000.”

Perhaps more baffling than their motive is why Tulloch and Parker, both well-liked, solid students at Chelsea Public School, would methodically plan to rob and murder people to finance their dream. “I could give you a whole list of kids who were more likely to try something like this,” says retired county sheriff Sam Frank, who had dealt with both teens when they were previously picked up for juvenile offenses that included breaking and entering. “They didn’t raise a flag like some of our repeaters.”

Far from being misfits, the boys camped out, played sports and dated just like any of their classmates. Parker, known as the school cutup, was one of two children born to John Parker, 53, a builder, and his wife, Joan, 52, a part-time teacher’s aide. A good athlete and avid keyboard player, Parker was something of a sidekick to Tulloch, one of four children born to Michael Tulloch, 46, a carpenter, and Diane, 46, a nurse. (Both sets of parents have refused to speak to the press.) A onetime student council president and debating team star, Tulloch apparently masterminded the crime, convincing Parker that they should become “badasses,” as Parker later admitted to authorities. “It was our sense,” said prosecutor Ayotte, “that Tulloch was the leader.”

At first the duo decided to steal cars, but soon dropped the idea when they realized they couldn’t sell a vehicle without its title. According to Parker, it was Tulloch who conceived the scheme to steal ATM cards, then kill the owners after they revealed their PIN numbers. The duo scouted homes in Vershire, Vt., and on July 19, 2000, armed with old carving knives, knocked on the door of a home on Goose Green Road. When the owner answered with a gun in his hand, the boys fled.

For weeks, they scouted other homes and researched weapons. On Jan. 1, 2001, they bought two 12-in. SOG SEAL 2000 combat knives with matching plastic sheaths. On the morning of Jan. 27 the teens drove Parker’s green Subaru 25 miles to Etna, N.H. Planning to gain entry to a home by pretending to be students doing an environmental survey, they parked on secluded Trescott Road and knocked on the door of the home of Dr. Bob McCollum, retired dean of Dartmouth Medical School. No answer.

Tulloch and Parker then tried the house next door, which belonged to Half and Susanne Zantop. Both German-born professors—Half, 63, taught earth sciences, while Susanne, 55, his wife of 30 years, was head of German studies—they were a witty, civic-minded couple who “showered love and affection on each other, their families and all the people they came in contact with,” colleague Irene Kacandes said at the April 4 hearings. On the day they died, the Zantops—parents to two grown daughters, Veronika, 30, a doctor in Seattle, and Mariana, 28, an international-aid worker in New York City—were home preparing a big European-style dinner for a friend.

It was Half who answered the knock on the door and led the boys into his study to help them with their survey. Ironically, the killers came across two people who were deeply involved in teaching and the environment, making them ideal victims. “Their vulnerability came from the sorts of people they were,” says Dartmouth president James Wright, who was close to the couple. “The kind of people who opened their doors to students.” While Susanne worked in the kitchen, her husband answered questions for 10 minutes. When the interview ended, Half, whose name in German means “to help,” opened his wallet to find the number of an environmental expert he knew. At that point, said Ayotte, the boys “noticed that there was quite a bit of cash” in the wallet.

Tulloch then pulled one of the knives from his backpack and lunged at an unsuspecting Zantop. He stabbed him in the chest and face, while Half struggled mightily. The professor’s piercing screams brought Susanne to the room, but Parker grabbed and held her. Then, said Ayotte, Tulloch “looked over at James Parker and told him to slit Susanne Zantop’s throat.” Parker did so, and Susanne fell to the ground. Next Tulloch slit Half’s throat and stabbed Susanne repeatedly in the head, fracturing her skull. The boys took Half’s wallet and fled. Their score: $340.

The killers burned their bloody clothes in a furnace in John Parker’s woodshop and drove to a Barnes & Noble to look for books on coping with the emotional aftermath of killing someone. After a colleague found the Zantops’ bodies, police discovered the knife sheaths that the boys had inadvertently left behind. Sales records for the knives led police to Tulloch and Parker, who were interviewed on Feb. 15. They claimed to know nothing of the crime, but that night snuck out of their homes and drove to Massachusetts, where they ditched their car and began hitch hiking across the country. Police finally caught up with them four days later in New Castle, Ind. “It’s a house of cards,” Tulloch said after he and Parker were arrested at a truck stop. “It took me 17 years to build, and I just blew it down.” Tulloch also repeatedly said, “I’m sorry, Jim.”

For the next several months the boys remained silent as they awaited trial. Then, last Nov. 30, Tulloch’s lawyers divulged that they were preparing an insanity defense. Faced with damning forensic and DNA evidence—police found the bloody knives in a box under Tulloch’s bed—as well as the prospect of his partner admitting to the crime, Parker abruptly cut a deal with prosecutors on Dec. 7, escaping a life sentence by pleading guilty to second-degree accomplice to murder, which carries a 25-to-life penalty. In exchange, he provided a mountain of details in interviews with police.

At his court appearance on April 4, the weight of his deeds finally came crashing down on James Parker. While prosecutors described the killings and the Zantops’ daughters gave a loving statement about their parents, Parker cried uncontrollably, his cuffed hands unable to wipe the tears from his eyes. “I’m sorry,” he stammered in between sobs in his statement to the court. “There’s not much more I can say than that.”

Tulloch, by contrast, showed no emotion or remorse in his separate hearing. He simply said “Guilty” three times when asked and made no statement. His surprise decision to plead guilty made him the first murder defendant in New Hampshire history to forgo any defense and, without any deal with prosecutors, accept a life sentence with no possibility of parole.

Tulloch and Parker have begun serving their sentences in separate prisons. Despite Parker’s plea deal, Tulloch “still considers Jim a friend,” says their sixth-grade teacher DeRoss Kellogg, who has visited both boys in prison. “Robert has a heart,” insists Kellogg, who is nevertheless stunned by their crimes. “I guess,” he adds, “most of us have a dark side.”

Why Tulloch and Parker descended so deeply into theirs remains a disturbing mystery. While justice may have been served, while the teens may have confessed to their sins, they failed to provide what some needed most: a satisfactory explanation. “What would cause two young members of our society to do these types of crimes?” prosecutor Ayotte says after being asked what drove the boys to murder. “I can’t answer that question for you.”

Alex Tresniowski

Eric Francis in New Hampshire