CHELSEA, Vt. – One way or another, Rob Tulloch and James Parker have been partners for nearly a decade – rafting rivers, climbing mountains and debating for their high school team.

According to friends and neighbors, the pair did everything together. According to authorities, that included murder.

Tulloch, 17, and Parker, 16, known around Chelsea mostly for their cocky, mischievous attitudes, are accused of killing two Dartmouth College professors in their Hanover, N.H., home three weeks ago. The teens were arrested Monday at an Indiana truck stop.

Authorities have refused to discuss a motive or any connection between the boys and the victims, who were stabbed repeatedly. Friends and acquaintances in this isolated town of 1,200 people are grasping for an explanation.

To them, Parker was the class clown and Tulloch was an honors student who had earned enough credits at Chelsea Public School to graduate early.

“Whatever he did, there was a reason for it,” said Kip Battey, Tulloch’s friend and a fellow debater. “He’s really smart, very logical. Everything he did, there was a reason for it.”

Both boys come from well-respected families. Their fathers are carpenters, and Parker’s was known for his work with the community’s recreation program. He also coached basketball and helped build the town’s soccer and baseball fields.

“These kids were average teen-agers,” said John Upham, owner of a variety store. “There was nothing extraordinary about them. There was nothing that would lead you to believe that they could do the crime they are accused of.”

But not everyone speaks so highly of the boys. Some suggested their families were too permissive.

“This does not surprise me in the least,” Robert Childs, the town property assessor, told The Boston Globe. “These kids weren’t coming home from a job after school. These kids were unsupervised and on the streets.

“They aren’t pillars of the community. Jimmy Parker wasn’t quite wild, but his parents were permissive, [and he’s] shunned by a major population of the school.”

But as far as most of the community is concerned, any mischief the boys were involved in was minor – they liked their paintball guns (using them on neighbors’ trees and lawns), clowning around in school and loved to speed along the town’s narrow roads.

Encounters with police had been mostly stay-out-of-trouble-type talks, boys-will-be-boys type stuff, according to Steve Watson, who owns the town video store.

“It’s going to take a long time for me to believe these kids were involved,” he said

Both boys were considered part of the school’s preppy crowd, which friends said avoided drugs, alcohol and smoking. In school, they were considered brains. Both joined the debate team, though Tulloch, a senior, took it more seriously than Parker, a junior.

Battey said Tulloch and Parker had known each other since they were about 10, roughly when Tulloch moved to the area. He said Tulloch was smart enough to be able to do anything he wanted in life – and he knew it.

“He knew that he was smart and he could boast about it,” Battey said. “Sometimes he carried himself very confidently” and that could grate on people, especially teachers.

He also said Tulloch had dreams of leaving Chelsea to explore foreign countries but had no definite plans and hadn’t applied to any colleges. With so many credits earned, friends said, Tulloch often spent as much as six hours at a time surfing the Internet.

Orange County Sheriff Dennis McClure has said the boys became suspects in the Dartmouth case after authorities learned one of them had bought a military-style knife online. The manhunt began after the boys voluntarily provided their fingerprints to authorities last week.

The professors, Half and Susanne Zantop, were found stabbed to death in their home on Jan. 27. Police have said Zantop, 62, was stabbed in the abdomen and his wife, 55, died trying to save him.

Shortly after the murders just 20 miles away, Parker and Tulloch left town, telling friends they wanted to go rock climbing in Colorado. They returned after a cut on Tulloch’s leg became infected.

While home, they acted normally, hanging out with friends, going to movies. Then they disappeared until last Thursday, when they provided their fingerprints.

They now face two counts of first-degree murder. Tulloch has waived extradition from Indiana but a hearing for Parker was delayed.

Evidence explaining what might have turned otherwise good boys bad is scant. The Parkers have not spoken with the media. Tulloch’s mother, Diane, has said only that she loves her son and he is innocent until proved otherwise.

“I have not been able to work these images into my brain,” said Tim Courts, a neighbor of Tulloch’s. “That’s what we’re all hoping, just that there’s been some mistake, that they were there, but they didn’t do it, because we just can’t imagine it. I can’t imagine it.”