A New Hampshire man charged with vehicular manslaughter after an accident on the Vineyard last July that killed his son and his son’s girlfriend pleaded guilty to a lesser charge last Friday in Edgartown district court.

In an emotional scene at the courthouse, Thomas C. Jones, 54, pleaded guilty to negligent operation of a motor vehicle in the July 4, 2012 accident that led to the deaths of his son, Seth Jones, and Heather Laflamme. Two counts of motor vehicle homicide by negligent operation were dismissed. Judge Bernadette L. Sabra accepted a joint sentencing recommendation of two years in a house of correction, suspended for four years. Mr. Jones was placed on probation for four years as well, until May 24, 2017.

Ms. Laflamme’s parents and grandmother, who live in Berlin, N.H., were in the courtroom, as were several members of the Jones family. Mr. Jones, a resident of Milan, N.H., was also ordered to complete 200 hours of community service, not to be charged and convicted with any subsequent offenses, and to pay $500 in fines plus an additional $50 monthly probation services fee. Cape and Islands assistant district attorney Laura Marshard recounted the facts of the case.

On July 4 last year Mr. Jones was driving a 2012 Jeep Wrangler, operated from the right side, on Barnes Road with his wife, Margaret in the passenger seat and Seth Jones and Ms. Laflamme in the back. The Jones family was on a vacation on Martha’s Vineyard.

Mr. Jones pulled the car into a U-turn to turn southbound while a Volkswagen Tiguan driven by Benjamin Johnson, then 19, of Cambridge, was driving northbound. The Volkswagen, later determined to be traveling 68 miles per hour, struck the left side of the Jeep. Seth Jones and Ms. Laflamme were ejected from the vehicle. Ms. Laflamme, 21, died three days later at a Boston hospital from injuries resulting from the crash. Seth Jones, 26, died two weeks later, also from injuries from the crash.

Tom and Margaret were both hurt in the accident, but did not have life-threatening injuries.

Ms. Marshard said that an investigation showed that Mr. Jones was negligent when he crossed northbound traffic, though the speed of the Volkswagen was also a factor in the crash.

Ms. Laflamme’s parents and grandmother, wearing buttons with Heather’s face on them and shirts in her honor, made emotional victim impact statements before the court.

“This is so hard for us to put how we feel onto paper,” said Paulette Laflamme, Ms. Laflamme’s mother. “We still can’t believe we will never get to hug her or hear I-love-yous.”

Mrs. Laflamme, wearing a shirt emblazoned with a picture of Seth and Heather and “We love you — Mom and Dad” written below it, said Jan. 25 would have been Heather’s 22nd birthday, and she would have graduated from the University of New Hampshire, where she was an honor student, last week. She worked at Walmart, her parents said, had a beautiful singing voice and volunteered.

Mr. Jones, the eldest of four brothers, was a Marine who served active duty in Iraq and Afghanistan.

“You killed Heather and Seth,” Mrs. Laflamme said to Mr. Jones in a courtroom where the air was thick with emotion Friday morning. “What you did to us is unforgivable because you never apologized to us,” Mrs. Laflamme said.

“It hurts so much,” Heather’s father Dicky Laflamme said in a tearful statement. “Some days I don’t know if I’m ever going to be okay, because it will never be the same again.”

“Thanks to you, Tom Jones, I will never get to walk my baby girl down the aisle,” he said. “You never apologized to us for killing Heather and as a parent you should have done that. You should have pleaded guilty to all counts and taken it like a man.”

Theresa Pepin, Ms. Laflamme’s grandmother, asked Mr. Jones to look at a picture of Heather and Seth that was on her shirt.

“I see them every day, ma’am,” Mr. Jones responded.

Ms. Marshard read an impact statement from Crystal Laflamme, 24, Heather’s sister. In the statement she recalled getting a call from the Massachusetts state police that her sister had been in an accident, and calling her parents to deliver the news. She said her young daughter asks for her aunt.

“It felt like a bad dream,” read Ms. Marshard, stopping to wipe her eyes with a tissue. “I never would have thought last Christmas when I said goodbye and I love you that it would be the final goodbye. Tom deserves to pay for what he has done. He took away two beautiful lives. He has no remorse for what he has done,” Ms. Laflamme wrote.

“It was a terrible accident and I’m deeply sorry,” Mr. Jones told the court. “I didn’t do it on purpose. I didn’t kill them on purpose . . . that would be insane. I’m not a coward,” he said.

“There’s been a lot of tragedy on all counts,” Judge Sabra said. “Certainly from Heather’s family’s point of view they’ve suffered an insurmountable loss.” She thanked them for coming, and said, “My heart goes out to you for your loss.”

“I can see from the facts that you are not alone in suffering significant loss,” she added. “I’m sure there’s nothing this court could ever do to replace this loss.”

“Mr. Jones really has a life sentence in many regards,” the judge said, adding that he would be haunted by what happened for the rest of his life.

She accepted the plea recommendation “with the hope that at least this part of things can be brought to a conclusion so you can continue on, for everyone, the healing process, the grieving process.”

Following the proceeding, Mr. Jones’s attorney Charles Goddard told the Gazette: “I feel sorry for the Laflammes. But I feel sorry for Mr. Jones, too. He’s going to have to live with the fact that he played a part [in his son’s death] for the rest of his life.”

The Joneses were married across the street from the courthouse at St. Elizabeth’s church, Mrs. Jones said after the hearing, sheltering from the rain under a courthouse awning, and Seth was born on the Vineyard. His 27th birthday would have been next Saturday.

“Everybody lost. We lost our son, and it was an accident,” she said. “It’s tough all around.”