DOVER, N.H. — Three young men, one of them from Sanford, Maine, face the possibility of life in prison after being charged Thursday with the premeditated stabbing death of a teenager whose body was dumped last weekend in Lebanon, Maine.

Zachary Pinette, 18, of Sanford appeared Thursday in Dover District Court to be formally charged with the first-degree murder of Aaron Wilkinson.

His co-defendants, Michael Tatum, 21, of Barrington, New Hampshire, and Tristan Wolusky, 18, of Rochester, New Hampshire, appeared from the Strafford County Jail through a video link.

The three are charged with killing Wilkinson outside his house in Madbury, a small town next to Dover. Pinette drove them there from Maine after midnight on Saturday, and held a machete as the other two stabbed Wilkinson with knives and then the machete, according to documents filed by prosecutors.

The documents say that at 1:30 a.m. Saturday, Pinette aided Wolusky and Tatum in committing first-degree murder. The documents also say that Tatum stabbed Wilkinson with a knife, and that Wolusky used a “knife and/or machete.”

Assistant Attorney General Jeffery Strelzin, head of New Hampshire’s homicide unit, would not disclose what police believe was the motive for the killing, saying that affidavits in the case have been sealed at the state’s request.

Strelzin would not say why the state sought to seal the affidavits. Wolusky’s attorney, Tim Landry of the New Hampshire public defender’s office, said he may seek to have them unsealed.

All three suspects declined requests for interviews with the Portland Press Herald, according to jail officials.

Wilkinson, who was 18, faced felony drug distribution charges from a traffic stop in Exeter in November. An attorney familiar with that case said none of the three suspects was involved in it.

The murder charges shocked people who knew all four young men and believed they were friends.

“(Wilkinson) would hang out with them. He would skate(board) with them, go to their house and stuff,” said Chris Cote, a longtime friend of Wilkinson who attended Thursday’s court hearing.

Cote said he was shocked that Wilkinson, who was known as peaceful and non-confrontational, could come to such a violent end. Cote teared up during the court hearing and wept later while being interviewed by reporters.

“Aaron was just too good for this, and especially with a machete,” Cote said. “Stabbing is personal. They wanted him to suffer slowly.”

Cote said Wilkinson was loved by his friends and family. “I love him like a brother,” he said.

Cote erected a shrine on Long Swamp Road in Lebanon, where Wilkinson’s body was found Saturday afternoon, and has visited it every day since his death.

He said the only motive he could think of was jealousy, because Wilkinson had many friends and an attractive girlfriend. “Tristan had nobody and Zach looked like a goon,” Cote said.

He said he knew the three suspects from Dover High School.

Hours before he was arrested and charged with Wilkinson’s murder, Tatum wrote on his Facebook page that he planned to attend a vigil for Wilkinson on Friday night at Swasey Parkway in Exeter.

Tatum’s Facebook page also has a banner with two Confederate flags, and on it he says he likes to burn things. He also posted a picture of himself in 2011, standing in front of a shed holding a rusty machete.

Madison Scamman, a friend of Wilkinson, said she was stunned by the news of his death and at least one of the suspects. She spent a lot of time with Wolusky last summer.

“I’m really shocked about Tristan,” she said. “He’s a big baby. He’s a really nice kid who just acts tough.”

Pinette’s cousin, Tina Pinette, said she was surprised by the charges. Pinette’s father died last winter of pneumonia and he took it hard, she said, but that wouldn’t explain the allegations against him.

“I can’t see Zach doing anything like that,” she said.

Pinette’s Facebook page says he attended Dover High School, but students there said they couldn’t remember him attending recently. Other acquaintances said he graduated this spring from Sanford High.

Cote’s mother, Kenesa Rivers, said Wilkinson had a slight build, smaller than her son, and the other three are burly. She said one of them posted a photo on Facebook showing all three flexing their muscles.

The three murder suspects will be held without bail until their next court appearance, at 11 a.m. on July 14.

Jonathan Cohen, the attorney representing Tatum, said he could offer little explanation for what the state says happened.

“My client is a young man who is facing a very serious accusation,” Cohen said. “He enjoys a presumption of innocence.”

Authorities said the three suspects were arrested at different locations and at different times Wednesday night, but said little about how they were tracked down.

Anna Sullivan, whose granddaughter Jade Olsen was close to Wilkinson, said her granddaughter got a text message from him at 1 a.m. Saturday but she was sleeping at the time so she didn’t respond. It said only “Hey.”

That message led New Hampshire State Police to interview Olsen.

Sullivan said it was her understanding that Wilkinson’s father woke Saturday and found his son not at home, which wasn’t unusual, but he also found blood. He reported him missing that morning. Sullivan said police determined that the blood had been there since between 1 and 2 a.m.

Wilkinson reportedly woke his father to tell him that someone was coming to visit late that night, so he wouldn’t feel he had to get up, Sullivan said.

Strelzin, the assistant attorney general, said the crime didn’t happen in the house, but he would not say where on the property it occurred.

Sullivan said her granddaughter is taking Wilkinson’s death extremely hard, and the manner of his death is so much harder because he was such a gentle person.

“He was quiet,” she said. “He had the most beautiful smile. He lit up the place. You couldn’t help but smile back.”