WASHINGTON (AP) - The Supreme Court won't upend the conviction of a Massachusetts woman who sent her boyfriend text messages urging him to kill himself.

Michelle Carter is serving a 15-month sentence after being convicted of involuntary manslaughter in the 2014 death of her boyfriend, Conrad Roy III.

A judge determined that Carter, who was 17, caused the death of the 18-year-old Roy when she ordered him in a phone call to get back in his carbon monoxide-filled truck that he'd parked in a Kmart parking lot.

Carter's case has garnered national attention and sparked legislative proposals in Massachusetts to criminalize suicide coercion.