TAUNTON, Mass. >> A Massachusetts woman who encouraged her boyfriend to kill himself in dozens of text messages and told him to “get back in” a truck filled with toxic gas faces up to 20 years in prison when a judge sentences her on a charge of involuntary manslaughter.

Michelle Carter was convicted in June by a judge who said her final instruction to Conrad Roy III caused his death. Juvenile Court Judge Lawrence Moniz will sentence Carter Thursday.

Carter was 17 when the 18-year-old Roy was found dead of carbon monoxide poisoning in July 2014.

In dozens of text messages, Carter urged Roy to follow through on his talk of taking his own life. “The time is right and you are ready … just do it babe,” Carter wrote in a text the day he killed himself.

The sensational trial was closely watched on social media, in part because of the insistent tone of Carter’s text messages.

“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 one text.

Carter’s lawyer, Joseph Cataldo, argued that 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 that Carter’s words amounted to free speech protected by the First Amendment.

In convicting Carter, the judge focused his ruling on Carter telling Roy to “get back in” after he climbed out of his truck as it was filling with carbon monoxide and told her he was afraid.

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

Carter and Roy met in Florida in 2012 while both were on vacation 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 Roy had made earlier suicide attempts.

Roy’s aunt has asked the judge to sentence Carter to the 20-year maximum. Carter’s father said his daughter made “a tragic mistake,” and is asking for probation and continued counseling.

Carter was tried as a youthful offender, so the judge has several options for sentencing. He can commit her to a Department of Youth Services facility until she turns 21 on Aug. 11. He could also combine a DYS commitment with an adult sentence, or can give her an adult sentence of anything from probation to the maximum 20-year term.