By Brian Ellsworth
FORT LAUDERDALE (Reuters) -A prosecutor on Monday told jurors they should sentence to death the gunman who killed 17 people and wounded another 17 in a mass shooting at a Florida high school in 2018.
Nikolas Cruz, 23, pleaded guilty in October to the premeditated murder of 14 students and three staff members at Marjory Stoneman Douglas High School in Parkland, about 30 miles (48 km) north of Fort Lauderdale.
Prosecutor Michael Satz told Broward County jurors on the first day of the penalty phase of the trial that Cruz committed "goal-directed planned, systematic murder -- mass murder -- of 14 students, an athletic director, a teacher and a coach."
Satz called witnesses, including students who were at school that day -- studying Shakespeare, the Holocaust -- and played cellphone videos in which terrified students cried for help or spoke in hushed whispers as they hid.
Around three dozen family members of the victims were present in court, some of whom cried as they watched the proceedings. Dressed in a gray-and-black sweater and wearing a black mask, Cruz sat with his head in his hands, at times resting his head on the defense table, as videos played.
Cruz, who was a 19-year-old expelled student at the time of the massacre, will be sentenced to life in prison without parole if any of the 12 jurors objects to the death penalty. Their decision could take several months.
Cruz in his guilty plea said he was "very sorry" and asked to be given a chance to help others. Satz said aggravating factors in the case, including premeditation, outweighed arguments for leniency, including Cruz's history of mental health problems.
Student Dylan Kraemer was in a Holocaust history class on the day the shooting when he heard a loud noise.
"Eventually the shooter started shooting through the window, bullets were flying through," he said. "We ducked down, waited 20 or 30 seconds, it stopped. I looked over and two people were dead, multiple people were shot."
Teacher Brittany Sinitch described calling the 911 emergency number from her classroom. Her students were writing Valentine's letters as characters from "Romeo and Juliet" as the attack began on the afternoon of Feb. 14, 2018.
"Almost instantly, I called 911. They couldn't hear me over the sound of the gunshots; it was so loud," she said.
Lawyers for Cruz were expected to make their opening arguments later in the proceedings.
U.S. gun violence has gotten renewed attention following recent mass shootings including one at an Independence Day parade outside Chicago that killed seven people, and another in May at a school in Uvalde, Texas, that left 19 children and two teachers dead.
President Joe Biden in June signed the first major federal gun reform in three decades, which he has celebrated as a rare bipartisan agreement.
(Reporting by Brian Ellsworth; Editing by Donna Bryson, Richard Chang, Jonathan Oatis and Cynthia Osterman)