Roy, who was a year older than Carter took his own life in 2014 when she was 17 years old.
The judge handing the verdict on Thursday to Carter, who had been convicted in June, said her final instruction to Roy after he expressed second thoughts had caused his death, Media reported on Friday.
The trial determined that she was “personally aware that her conduct was both reprehensible and punishable” for involuntary manslaughter. .
The court found that through a stream of text messages and cellphone calls, Carter had established a “virtual presence at the time of the suicide.”
Roy died in July 2014 in Fairhaven from carbon monoxide poisoning after he connected a generator to a truck’s exhaust system. Roy and Carter spoke by phone for 47 minutes while he sat in the truck, and she allegedly told him to “get back in” the vehicle when he expressed doubts about taking his own life.
In its ruling, the court found there was probable cause to show that “the coercive quality of the defendant’s verbal conduct overwhelmed whatever willpower the 18-year-old victim had to cope with his depression.”
“But for the defendant’s admonishments, pressure, and instructions, the victim would not have gotten back into the truck and poisoned himself to death,” Justice Robert Cordy wrote in the ruling.
Legal experts said the decision broke new ground.
The jail sentence was the first time a defendant was convicted on “the basis of words alone.”
Boston College law professor R. Michael Cassidy said the ruling represents an “incremental change” in the legal interpretation of involuntary manslaughter.
The Boston law professor said the girl’s instructions to the boy, inciting him to harm himself had passed the threshold of counseling, advice and suggestion.
“She basically bullied him into the act,“ Cassidy said.
In the moments before his suicide, Carter advised her suicidal boyfriend to kill himself.
“You need to do it, Conrad … you will be free and happy.”
She had faced a maximum sentence of 20 years, but her legal team argued that both she and her boyfriend suffered from mental illness.