Michelle Carter, the Massachusetts woman convicted of involuntary manslaughter for encouraging her boyfriend to kill himself will serve at least 15 months in prison.

Prior to the sentencing, there were calls for her to get up to 20 years in jail. Carter looked distraught during the sentencing as she learned her fate for her role in the death of Conrad Roy III.

Juvenile Court Judge Lawrence Moniz handed down a two-and-a-half year sentence on Thursday (3 August) with the remainder to be suspended when she would be eligible for probation.

She was found guilty of involuntary manslaughter last month after she sent Roy dozens of messages urging him to take his own life, including instructions to "get back in" a truck filled with toxic gases during the final moments of his troubled life.

"You can't think about it. You just have to do it. You said you were gonna do it. Like I don't get why you aren't," she wrote in another text.

At trial, it was put to Carter that she had urged her boyfriend to take his own life so she could revel in the attention of the "grieving girlfriend" role.

Carter was tried as a youth offender as she was 17 when Roy ran a generator exhaust into his vehicle and died of carbon monoxide poisoning in July 2014. He was 18 at the time.

During his summary, Moniz described Carter's instruction to Roy to return to the poison-filled chamber as "wanton and reckless conduct". He passed the same judgement on her decision not to alert authorities or Roy's family to his death.

The pair exchanged more than 1,000 texts in the days leading up to Roy's death, many of which discussed the possible suicide attempt.

Shortly before his death, Carter texted: "So I guess you aren't gonna do it then, all that for nothing ... I'm just so confused like you were so ready and determined."

Carter's defence counsel had argued that Roy was obsessed with his own suicide and that Carter had initially tried to make him seek professional help before folding and going along with his plan.

Michelle Carter, The Woman Who Allegedly Encouraged Her BF To Commit Suicide
Michelle Carter was found guilty of the involuntary manslaughter of Conrad Roy III

It also emerged that Carter was receiving antidepressant medication which impairs the ability to be empathetic and make decisions.

However, in their closing arguments, prosecutors said Carter had been motivated by seeking special attention from her friends and that she listened in to his final moments on her mobile phone.

"It got to the point that he was apologising to her... apologising to her for not being dead yet," they said.

Carter went on to text message her friends about hearing Roy's final breaths and words over the phone. His body was found 13 July, 2014, a day after he died, in his parked truck in a Kmart car park in Fairhaven, nearly 40 miles from his home.

Michelle Carter
Michelle Carter was 17 when Roy killed himself Facebook