Michelle Carter, now 20, faces 20 years in prison if convicted of encouraging Conrad, who suffered from anxiety and depression, to end his life.
Conrad was found in his vehicle on July 13, 2014. He had died of carbon monoxide poisoning, but according to police the teen wouldn't have gone through with the act had he not been encouraged by Michelle.
Text messages sent between the pair in the week leading up to Conrad’s death included Michelle saying: "You always say you’re gonna do it, but you never do. I just want to make sure tonight is the real thing," and "You just have to do it."
She also wrote, "It’s painless and quick."
Police found Michelle's written admission to a friend in which she recalled Conrad calling her on the night, saying he was scared and didn’t want to abandon his family.
She wrote that she told him to "Get back in."
She later wrote to that same friend, saying, "His death was my fault … he got out of the car, and I told him to get back in … because I knew he would do it all over again the next day."
On Monday, the 20-year-old's trial began at Massachusetts’ Bristol County Juvenile Court.
If you are struggling with mental health, contact Lifeline on 13 11 14.
This article first published on Marie Claire.