detectives pored over thousands of text messages and they got their answer. >> lo and behold, on her phone there was text messages to her friends describing what that phone conversation was like. >> reporter: the detective says a message michelle sent her friend samantha boardman explained it all. "sam, his death is my fault, like honestly i could have stopped him. i was on the phone with him. and he got out of the car because it was working and he got scared and i f-ing told him to get back in." >> and as much as we were in shock about her language prior to that, once we read that, that was really disturbing. >> reporter: prosecutor flynn says another text message to that friend made it clear michelle knew what she'd done was wrong. >> she said, "sam, i just found out from his mother that the detectives have some of his things and are-- are going through them to see if anybody texted him or encouraged him. they read my text messages with him and i'm done, his family will hate me, and "i could go to jail." >> reporter: and that's what was at stake on june 5, 2017, almost