BOSTON — The woman convicted of involuntary manslaughter after she texted her suicidal boyfriend encouraging him to kill himself is appealing her conviction Thursday.

The Massachusetts Supreme Judicial Court will hear arguments today from Michelle Carter's defense attorneys in an effort to overturn the conviction and the 15-month prison sentence. Carter has remained free as her appeal is pending.

Carter was 17 years old when she texted Conrad Roy III to "get back in" his truck as it filled with deadly carbon monoxide fumes in a parking lot in Fairhaven in July of 2014. Roy was 18 years old when he passed away in his truck.

Prosecutors say Carter could have prevented the suicide.

Carter's lawyers say her conviction criminalizes free speech. They also argue that her texts did not cause Roy's death, as he was a troubled teen with a history of mental illness and suicide attempts.