BOSTON, Mass. -- A Massachusetts woman convicted of involuntary manslaughter for urging her boyfriend in dozens of texts to go through with his suicide faces up to 20 years in prison at her sentencing Thursday.

Michelle Carter was found guilty in Taunton, Mass., in June by Juvenile Court Judge Lawrence Moniz.

The trial found that in 2014, Carter, then 17, urged her 18-year-old boyfriend, Conrad Roy III, in a text message to "get back in" a truck filling with carbon monoxide when he got momentarily scared.

The judge said Carter's text constituted “wanton and reckless conduct” under the manslaughter statute. He said Carter had a duty to call for help.

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

Because Carter was tried as a youthful offender, Moniz has several sentencing options, from committing her to a youth facility, to combining a youth services sentence with an adult sentence, to giving her an adult sentence ranging from probation to a maximum of 20 years in prison.

Roy’s aunt, Kim Bozzi, asked the judge for the maximum sentence. Carter’s father said his daughter made “a tragic mistake” and asked for probation and continued counseling.

According to the Boston Herald, Bozzi plans to speak at the sentencing and ask for the 20-year prison sentence, arguing Carter took “calculated” and “planned” action and “should be kept far away from society.”

Carter's "get back in" text was one of dozens of similar messages she sent Roy urging him not to back down. “The time is right and you are ready ... just do it babe,” Carter wrote in a text the day he killed himself.

“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,” Carter wrote in another text.

Carter’s lawyer, Joseph Cataldo, argued Roy was determined to kill himself and nothing Carter did could change that. He said Carter initially tried to talk Roy out of it and urged him to get professional help, but eventually went along with his plan. Cataldo also argued Carter’s words amounted to free speech protected by the First Amendment.

A day after Roy died, Carter posted a lengthy message on his Facebook page in which she mourned his death.

“I’m sorry I couldn’t save you, I’m sorry I let you do this,” she wrote, reported.

“I never thought I would have to live a day without him,” Carter said in the post, which was introduced by the prosecution during her trial in Bristol County Superior Court.

Contributing: Associated Press