Marjory Stoneman Douglas High School shooter Nikolas Cruz
Marjory Stoneman Douglas High School shooter Nikolas Cruz Carline Jean/Pool via REUTERS

The gunman who attacked the high school in Parkland, Florida, in 2018, returned to court on Monday for the penalty phase of his case in which a jury will decide whether he is sentenced to death or life in prison without parole, The Associated Press reported.

Nikolas Cruz, 23, pleaded guilty in October to 17 counts of first-degree murder in the deaths of 14 students and three staff members at Marjory Stoneman Douglas High School. He is contesting only his sentence.

A seven-man, five-woman panel, backed up by 10 alternates, will hear the case, which is expected to last about four months. The trial was supposed to begin in 2020, but it was delayed by the COVID-19 pandemic and legal fights.

Prosecutors said a month after the attack that they will seek the death penalty for Cruz.

Lead prosecutor Mike Satz on Monday highlighted Cruz’s brutality as he stalked a three-story classroom building and fired his AR-15 semi-automatic rifle down hallways and into classrooms. Cruz sometimes walked back to wounded victims and killed them with a second volley of shots, he said.

Satz described Cruz as “cold, calculated, manipulative and deadly,” citing a video Cruz made three days before the massacre.

“This is what the defendant said: ‘Hello, my name is Nik. I’m going to be the next school shooter of 2018. My goal is at least 20 people with an AR-15 and some tracer rounds. It’s going to be a big event, and when you see me on the news, you’ll know who I am. You’re all going to die. Ah yeah, I can’t wait.’”

The FBI admitted after the shooting it had received a tip that Cruz had a "desire to kill" and access to guns and could be plotting an attack, but agents failed to investigate.

A person who was close to Cruz had called the FBI's tip line before the attack and provided information about Cruz's weapons and his erratic behavior.

The FBI acknowledged that the tip should have been shared with the FBI's Miami office and investigated, but it was not.