The U.S. Supreme Court announced Monday it will not hear an appeal by the Massachusetts woman who sent her teenage boyfriend multiple text messages urging him to kill himself.

Michelle Carter, who’s serving a 15-month sentence for her role in the 2014 death of her boyfriend, was seeking to have her conviction for involuntary manslaughter overturned after losing an earlier appeal in the Massachusetts Supreme Court.

Her lawyers had described the case against her as “unprecedented” and filled with flaws, but Monday’s ruling confirms the conviction will remain in place.

The 23-year-old woman was found guilty of causing Conrad Roy’s death by telling him in a phone call to get back to his truck, which was filled with carbon monoxide. She also sent him dozens of text messages encouraging him to take his life in the days leading up to his death.

“You keep pushing it off and say you’ll do it but u never do. It’s always gonna be that way if u don’t take action,” Carter wrote in one of the messages.

Roy was 18 at the time; Carter was 17.

Her lawyers have tried to depict her as a misguide teenager whose actions may not have prevented Roy’s suicide.

The case drew national attention and sparked a legislative proposal in Massachusetts that would make coercing someone into taking their own life a crime punishable by up to five years in prison.