michelle carter had been arrested, charged with the death of conrad roy. chilling text messages michelle sent conrad who struggled with depression, urging him to kill himself. now the case was headed to trial, but could prosecutors prove what she'd done was a crime? once again, here's andrea canning with "reckless." >> reporter: michelle carter was facing involuntary manslaughter charges for doing something teenagers do all the time -- texting and calling each other. and the world was watching. prosecutors, mary claire flynn and katy rayburn, understood why. this affects everybody, adults, teenagers, even parents with kids who don't even have phones yet. >> absolutely. i think it's good to be thinking about what you're putting out in the world. once you send it, you can't take it back. >> turn the gears. >> reporter: prosecutors believed michelle's words and actions caused a vulnerable conrad to kill himself. he described his fragile state in that video diary. >> racing thoughts. suicidal thoughts. flashbacks of hard times. >> reporter: and prosecutors lear