A Plainville 18-year-old is facing criminal charges for allegedly encouraging her friend to commit suicide, according to the Bristol County District Attorney’s Office, which is basing its case on a search of the victim’s cell phone.

Michelle Carter “encouraged” her friend Conrad Roy, 18, of Fairhaven, “to commit suicide and guided him in his engagement of activities which led to his death,” according to a statement by DA spokesman Gregg Miliote.

Roy was reported missing July 13 by his family, according to Miliote. His body was found that day in his parked car, and police believe he committed suicide by carbon monoxide poisoning.

“A subsequent search of Roy’s cell phone led to a joint investigation by Fairhaven Police and State Police Detectives assigned to the district attorney’s office,” Miliote said. “Based on the totality of the investigation, it is alleged that Ms. Carter had first hand knowledge of Roy’s suicidal thoughts. 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.”

Carter was indicted as a youthful offender on Feb. 6 on a charge of involuntary manslaughter.

New Bedford Juvenile Court Judge Siobhan E. Foley set bail in the amount of $2,500 cash, and set conditions that Carter have no internet access other than for school assignments; no access to any social media; no text messaging with anyone other than her parents.

Carter is due back in New Bedford Juvenile Court for a pretrial hearing April 17. Because she is 18, she will be tried as an adult.

District Attorney Thomas Quinn has recused himself the case due to a “familial relationship” with the victim’s family, Miliote said.