Police in Massachusetts have charged an 18-year-old honor student with involuntary manslaughter for her alleged role in the death of classmate Conrad Roy, 18, who took his own life last July.

According to prosecutors, Michelle Carter of Plainville, Massachusetts "strongly influenced" Roy's decision to kill himself, privately advocating he poison himself with carbon monoxide while publicly expressing concern about the missing teen's whereabouts and safety. From The Boston Globe:

After writing one friend to say, "I'm losing all hope that he's even alive," Carter texted Roy, "Let me know when you're gonna do it," according to a police report. Carter, now a senior at King Philip High School, had a "full understanding" of the suicide plan, and in the days leading up to Roy's death "not only encouraged Conrad to take his own life, she questioned him repeatedly as to when and why he hadn't done it yet," the report said.

Emphasis added. Prosecutors say at one point Roy expressed concern for his family and became scared, exiting the truck he was later found dead in. According to court documents, Carter told Roy "get back in."

In the months after his death, Carter mourned Roy over social media tweeting "Such a beautiful soul gone to soon" and "#WeCanEndSuicide."

I will never understand why this had to happen — Michelle Carter (@michyc47) July 16, 2014

Carter, who was 17 at the time, has now been charged as a youthful offender and faces up to 20 years in prison, but her attorney says there was no crime.

"They're trying to claim there is manslaughter when they freely admit the boy took his own life," attorney Joseph P. Cataldo told The Standard-Times. "You can't have it both ways."

[Image via WBZ-TV//h/t Huffington Post]