The mother of Conrad Roy has filed a $4.2 million wrongful death lawsuit against Michelle Carter, following Carter's manslaughter conviction for pressuring her son into suicide.

Carter was sentenced Thursday to two and a half years in jail, with 15 months to be served and the rest suspended until 2022. But the judge in the case approved a stay in the execution of the sentence until Massachusetts courts rule on her appeal, meaning that for now she remains free under probation conditions.

In the suit, filed in Norfolk Superior Court on July 6, Lynn Roy claims that Roy's death has caused $4,224,000 in reasonably anticipated lost wages, citing the captain's license he obtained shortly before his suicide as evidence of his earning potential.

Carters' negligence and reckless conduct caused Roy to sustain "severe personal injuries, great conscious pain and suffering of body and mind and ultimately death," the suit alleges.

Attorney Eric Goldman, one of the lawyers representing Lynn Roy in the suit, said the goal is to establish a memorial for Conrad, not profit financially.

"The family would obviously rather have their son back," Goldman said. "What the Roys are looking to do is somehow memorialize Conrad."

Daniel Medwed, a professor at the Northeastern University School of Law, said that wrongful death suits often focus on lost future earnings as the most concrete economic damages that arise from a loss of life.

"There's often debate or battle over what those earnings might be, especially with teenagers," he said. "How do you speculate what earning potential is when we all evolve?"

Many wrongful death suits end in a settlement and the $4.2 million claim could be a baseline for those negotiations, Medwed said. But members of the Roy family, some of whom voiced dissatisfaction with the stay in Carter's sentence yesterday, could also see the case through to a jury if they want a more public form of justice.

"Part of it depends on if this is a message lawsuit where they really want their voices heard," Medwed said.

Goldman said no settlement talks had begun but that the family is open to negotiations.

Carter's attorney Joseph Cataldo did not immediately respond to requests for comment.

Roy, 18, was found dead on July 13, 2014, after parking his truck in a Kmart parking lot after he turned on a gas-powered water pump and allowed the cabin to fill with carbon monoxide.

Carter, who was 17 years old when she sent Roy a barrage of texts and Facebook messages encouraging him to kill himself before his eventual suicide, was convicted of a count of involuntary manslaughter in Taunton Juvenile Court on June 16.

Taunton Juvenile Court Judge Lawrence Moniz ruled in June that phone calls Carter made to Roy in the minutes before his death directly caused his suicide and justified the manslaughter charge, which carries a sentence of up to 20 years in prison.

In those phone calls, Carter told Roy to "f------ get back in" his truck as it filled with carbon monoxide after he expressed fears of following through on his suicide plan, according to text messages she sent to friends after his death.

The judge ruled that it was reasonable to assume that Roy would not have gone through with the suicide but for Roy's command to get back in the truck.

The Roy's lawsuit cites the phone calls, as well as text messages in which Carter "specifically instructed" Roy to use a generator and told him to kill himself while others were asleep.

"While the generator was still running in the vehicle, Mr. Roy exited the vehicle because he was scared. Despite understanding the dangerous conditions inside the vehicle, Ms. Carter ordered Mr. Roy to get back into the vehicle."

Text messages introduced as evidence in the trial show that while using carbon monoxide as a suicide method was originally Roy's idea, Carter encouraged and pressured him into following through.

"Do you have the generator?" Carter texted Roy in the days before his death.

"Not yet lol," he responded.

"WELL WHEN ARE YOU GETTING IT," she replied.

Carter's manslaughter conviction increases the lawsuit's chances of success, Medwed said. Moniz already ruled that Carter's actions were "wanton" and "reckless," two standards of Massachusetts' wrongful death statute -- and did so in criminal court, where the burden of proof is much higher.

And the Roy's attorneys have evidence introduced at trial at their disposal, making it easier to proceed, Medwed added.

"You don't have to call all those witnesses again," Medwed said. "You don't have to reinvent the wheel."