Jurors decided on Thursday that Nikolas Cruz should be sentenced to life in prison for the 2018 Parkland, Florida, school shooting that killed 17 people.

Cruz, 24, pled guilty to premeditated murder at Marjory Stoneman Douglas High School last year. In one of the bloodiest school shootings in American history, he used a semi-automatic weapon to murder 14 pupils and three staff members.

During the three-month sentencing hearing, the prosecution contended Cruz’s act was both premeditated and heinous and cruel, which are among the criteria established by Florida law for deciding on a death sentence.

Cruz’s defense team had acknowledged the severity of his crimes but asked jurors to consider mitigating factors including lifelong mental health disorders resulting from his biological mother’s substance abuse during pregnancy.

Under Florida law, a death sentence could only have been handed down if jurors had unanimously recommended, he be executed. The only other option was life in prison.

Cruz, who at the time of the shooting was 19 and had been expelled from the high school, had apologized for his crimes and asked to be given a life sentence without the possibility of parole in order to dedicate his life to helping others.

The sentencing proceedings included testimony from survivors of the shooting as well as cellphone videos in which terrified students cried for help or spoke in hushed whispers as they hid.

The Parkland shooting had led to renewed calls for tighter gun control in the United States.

U.S. gun violence gained renewed attention following mass shootings this year at an elementary school in Uvalde, Texas, that left 19 children and two teachers dead, and another at a supermarket in Buffalo, New York, that killed 10 people.