Woman who encouraged boyfriend to kill himself could avoid prison

Michelle Carter told Conrad Roy III to 'get back in' a truck filled with toxic gas

Defence lawyer Joseph Cataldo talks to his client, Michelle Carter, during the trial (Faith Ninivaggi/The Boston Herald/AP)

A woman who encouraged her boyfriend to kill himself with dozens of texts messages, including one that told him to "get back in" a truck filled with toxic gas, could avoid a jail sentence.

Michelle Carter was convicted of involuntary manslaughter in June after a judge ruled that her final instruction to Conrad Roy III caused his death from carbon monoxide poisoning in July 2014.

Bristol County Juvenile Court in Massachusetts heard that Carter, then 17, had repeatedly messaged the 18-year-old Roy, before he took his own life.

"The time is right and you are ready ... just do it babe," Carter wrote in one message.

Another said: "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."

At trial it emerged that Carter and Mr Roy met in Florida in 2012 while both were on holiday with their families. After that, they only met in person a handful of times. Their relationship consisted mainly of texting.

Both teens struggled with depression. Carter had been treated for anorexia and Mr Roy had made earlier suicide attempts.

Carter's lawyer, Joseph Cataldo, argued that Mr Roy was determined to kill himself and nothing Carter did could change that.

He said Carter initially tried to talk Mr Roy out of it and urged him to get professional help, but eventually went along with his plan.

Mr Cataldo also argued that Carter's words amounted to free speech protected by the First Amendment.

Explaining why he had found her guilty, Judge Lawrence Moniz focused on Carter telling Mr Roy to "get back in" after he climbed out of his truck as it was filling with carbon monoxide. He had told he was afraid.

The judge said those words constituted "wanton and reckless conduct" under the manslaughter statute.

Ahead of the sentencing, Mr Roy's aunt Kim Bozzi, asked the judge to give Carter to the 20-year maximum sentence.

But her father said his daughter made "a tragic mistake," and is asking for probation and continued counselling.

As she was tried as a youthful offender, the judge has several options for sentencing. He can commit her to a Department of Youth Services (DYS) facility until she turns 21 on 11 August.

He could also combine a DYS commitment with an adult sentence which could lead to maximum 20-year term.

Alternatively, he could release her on probation with no time to serve.

Agencies contributed to this report