search of her phone reveals michelle sent a series of stunning text messages to classmate, samantha boardman, after conrad's death. when michelle hears detectives are searching conrad's phone, she sends samantha a frantic message. >> sam, they read my messages with him, i'm done. his family will hate me and i could go to jail. >> reporter: but it gets worse. two months after conrad's death, michelle sends samantha this jaw-dropping admission. >> 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 [ bleep ] and i told him to get back in. >> when he got out of the truck and said, "i can't do this. i'm not gonna do this," she said, "get back in the truck. suck it up." >> that is the saddest part of this whole story, the truck is filling up with carbon monoxide, and he gets out. and she tells her friend sam that she told conrad to get back in the truck. >> she did not call police. she did not call her parents, his parents, nobody. she sat there, waited for him to die and then texted he