The woman who as a teen encouraged her boyfriend’s suicide will serve her full sentence after the U.S. Supreme Court declined to hear her appeal.

Michelle Carter’s appeal appeared on a list on Monday titled “Certiorari Denied,” which means the high court won’t review those cases.

Carter, now 23, was convicted of involuntary manslaughter after Conrad Roy III took his life in a Kmart parking lot in Fairhaven, Massachusetts. Sentenced as an adult, she was given 15 months in prison.

Roy was 18 and Carter was 17 on July 12, 2014, the evening when he called her and talked of killing himself. At one point, he appeared to have second thoughts and she commanded him to “get back in” his carbon monoxide-filled pickup truck.

The phone call wasn’t recorded, and the judge relied on a text Carter sent her friend in which she admitted she told Roy to get back in the truck. In text messages sent in the days leading up to Roy’s death, Carter also encouraged him to follow through with his suicide plan, Massachusetts courts found.

Carter’s lawyer Joseph P. Cataldo called the Supreme Court’s decision “unfortunate” in an email to the Boston Herald on Monday and left the door open to other possible action in the case.

Cataldo had argued Carter’s conviction violated the First Amendment guarantee of free speech because it was based solely on words that she texted or spoke. An appeal on the same grounds was previously rejected by the Massachusetts Supreme Judicial Court.

Carter began serving her sentence in February 2019 at the Bristol County House of Corrections. Her request for early parole was denied in September.