Story highlights

Conrad Roy, 18, found dead of apparent carbon monoxide poisoning, police say

Prosecutors: Search of his phone found texts from Michelle Carter urging him to commit suicide

Defense attorney says Carter is innocent and tried to get Roy to undergo counseling

CNN  — 

A Massachusetts teenager faces a pretrial hearing in April on involuntary manslaughter charges for allegedly sending text messages urging a friend to commit suicide, even after he expressed second thoughts, authorities said Saturday.

“You need to do it, Conrad,” Michelle Carter wrote her friend in the early hours of July 12, 2014, according to the document. “You’re ready and prepared. All you have to do is turn the generator on and you will be free and happy. No more pushing it off. No more waiting.”

Later that morning, Conrad Roy, 18, left his mother’s home and drove to the parking lot of a Kmart, the document showed. He called Carter, spoke with her for more than 40 minutes and, at some point, got out of his truck “because (the carbon monoxide poisoning) was working and he got scared,” according to the document.

Carter told him to get back in the truck, according to her indictment. The next day, on July 13, police found his body in the truck; he used a combustion engine to fill the cabin with carbon monoxide.

Carter, 18, was indicted in February, but the text messages exchanged between the two were released late last month in a prosecution response to a defense motion seeking to dismiss the indictment.

Carter’s attorney, Joseph Cataldo, has maintained his client’s innocence, saying the evidence will show it’s not a manslaughter case and that Carter attempted to console Roy on many occasions. Cataldo said Roy had planned the suicide for months.

Cataldo said his client had repeatedly encouraged Roy to seek professional help and finally resigned herself that he would carry out his plan. The lawyer said the case was a “dangerous prosecution” in that it suggests “speech alone caused” the young man to kill himself.

Upon searching Roy’s cell phone, police discovered “hundreds” of texts between Roy and Carter, many which contained language from Carter that encouraged Roy to take his own life, Kobza said.

“Instead of attempting to assist him or notify his family or school officials, Ms. Carter is alleged to have strongly influenced his decision to take his own life, encouraged him to commit suicide and guided him in his engagement of activities which led to his death,” Gregg Miliote, director of communications for the Bristol County District Attorney’s Office, said in a statement.

“I think your parents know you’re in a really bad place…They know that you’re doing this to be happy and I think they will understand and accept it. They will always carry you in their hearts,” Carter wrote in one text.

“Aww. Thank you, Michelle,” he wrote back.

According to the document, Carter even offered technical advice on carrying out the suicide.

“If you emit 3200 ppm of (carbon monoxide) for five or ten minutes you will die within a half hour,” she wrote. “You lose consciousness with no pain. You fall asleep and die.”

On a Twitter page confirmed by the District Attorney’s Office to be Carter’s, several photos and tweets about Roy have been posted since his death. One tweet reads, “I can’t believe today already marks 4 months without you. I love you and miss you always Conrad…”

In September 2014, Carter organized a softball tournament in Roy’s memory and raised $2,300 for mental health awareness, according to Kobza.

Carter was arraigned on the indictment on February 6 in New Bedford Juvenile Court, released on $2,500 bail and told not to use social media, according to Miliote.

Carter was indicted as a youthful offender because she was not yet 18 when the alleged crimes occurred. Youthful offenders are tried in juvenile court but the proceedings are public, Cataldo said.

CNN’s Dominique Debucquoy-Dodley contributed to this report.