MICHELLE Carter, the woman who sent her boyfriend texts encouraging him to kill himself, has been found guilty of manslaughter.

The New York Post reports that Carter faces up to 20 years in prison after being convicted of involuntary manslaughter in the July 2014 suicide of Conrad Roy III, 18, who died in 2014 from carbon monoxide poisoning inside his pick-up truck.

Judge Lawrence Moniz said Carter was “mindful” of the toxic environment building in Roy’s pick-up truck yet encouraged the troubled teen to get back in the vehicle.

“She is mindful that the process in the truck will take approximately 15 minutes,” Mr Moniz said during Friday’s hearing.

Carter did that despite knowing “all of the feelings” Roy had shared with her previously, including a prior attempt to drown himself, Mr Moniz said.

“Instructing Mr. Roy to get back in the truck constituted wanton and reckless conduct, creating a situation where there’s a high degree of likelihood that substantial harm would result,” Mr Moniz said.

Carter then took no action to help Roy either by calling police or his family despite knowing his plan and location, Mr Moniz said.

“She did not issue a simple additional instruction: get out of the truck,” he continued.

Mr Moniz also banned Carter from contacting Roy’s relatives and ordered her not to obtain or apply for a passport. Carter is scheduled to be sentenced on August 3.

Text messages between the two shown in court revealed that Carter, then 17, told Roy to “get back in” the vehicle as it filled with the lethal gas.

“You can’t think about it,” Carter allegedly texted Roy on the day of his death. “You just have to do it. You said you were gonna do it. Like I don’t get why you aren’t.”

Prosecutors also noted that Carter sent a text to a friend from high school about two months after Roy’s death, admitting she was to blame.

“It’s my fault,” Carter texted to classmate Samantha Boardman. “I could have stopped him but I told him to get back in the car.”

Carter also told Ms Boardman she was worried about what investigators would find on Roy’s phone.

“I’m done,” Carter wrote in one message shown in court. “His family will hate me and I can go to jail.”

Mr Moniz presided over the two-week trial in Bristol Juvenile Court after Carter, now 20, waived her right to a jury trial and pleaded not guilty.

Prosecutors argued Carter encouraged and manipulated Roy to kill himself with repeated text messages and phone calls, telling him the process would be “painless.”

On the day of his death, Carter finally convinced Roy to follow through on the plan during a phone call telling him to return to his truck.

Carter’s lawyers, meanwhile, countered that the messages were protected free speech and that Roy had a history of depression and tried to kill himself during a previous suicide attempt.

Roy even researched suicide online before Carter encouraged him to take his own life and sent text messages to other people about suicide as well, lawyer Joseph Catalado said in court, MassLive.com reports.

Roy’s handwritten suicide note was revealed in court on Tuesday during the final day of Carter’s trial.

“I love you and greatly appreciate your effort and kindness toward me,” Roy’s note to Carter read. “ … I’m sorry I wasn’t the boy you wanted. I can’t take the pain. I did this to finally to be happy.”

If you are experiencing mental health issues or suicidal feelings contact Lifeline on 13 11 14 or Beyond Blue 1300 224 636. If it is an emergency please call 000.

This article originally appeared in the New York Post