The opening statements portion of the penalty trial for confessed Parkland, Florida, school shooter Nikolas Cruz is complete – for the time being – after defense attorneys on Monday opted to delay their statement until it is time to present their case in the following weeks. 

Prosecutors delivered their opening statements Monday morning at the Broward County Courthouse in Fort Lauderdale, where jurors will decide whether the 23-year-old will be executed or sentenced to life without parole for the 2018 massacre of 17 people at Marjory Stoneman Douglas High School in Parkland.

Cruz 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. It is the nation's deadliest mass shooting to go before a jury.

Earlier on Monday, the seven-man, five-woman panel, backed up by 10 alternates, heard statements from lead prosecutor Mike Satz.

PARKLAND SHOOTER NIKOLAS CRUZ: FLORIDA TRIAL BEGINS OVER WHETHER GUNMAN WILL FACE DEATH PENALTY

Nikolas Cruz, the Parkland school shooter, appears in court wearing an orange jumpsuit, glasses, and a mask

Marjory Stoneman Douglas High School shooter Nikolas Cruz speaks to his attorney Assistant Public Defender Nawal Bashimam, not shown, during a hearing at the Broward County Courthouse in Fort Lauderdale on Wednesday, March 29, 2022. (Amy Beth Bennett/South Florida Sun-Sentinel via AP, Pool)

Satz 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.

The prosecutor described Cruz as "cold, calculated, manipulative and deadly," citing a video Cruz made three days before the massacre.

FLORIDA JUDGE DENIES REQUEST FOR PARKLAND SHOOTER'S SENTENCING TO BE DELAYED

"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.’"

Diagram showing details of Parkland school shooting

Graphic gives details of the Marjory Stoneman Douglas High School shooting.

About 50 family members of the victims were in the courtroom, some couples holding hands. Some parents teared up as Satz described the deaths of their children. One mother, crying, got up and left. Others sat stoically, their arms folded across their chests.

PARKLAND TRIAL: DEFENSE TEAM FOR SCHOOL SHOOTER ASKED JUDGE TO WITHDRAW

It wasn’t clear if anyone was present to support Cruz, who sat at the defense table between his attorneys. He mostly looked down at a pad of paper with a pencil in his hand, but he did not appear to write. At times, he would look up to stare at Satz or the jury, peer at the audience or whisper to his lawyers.

After Satz spoke, Cruz's lawyers announced that they will not give their opening statement until it is time to present their case weeks from now. 

Police car and crime tape blocking entrance of Marjory Stoneman Douglas High School

Law enforcement officers block off the entrance to Marjory Stoneman Douglas High School Feb. 15, 2018 in Parkland, Fla., following a deadly shooting at the school.  (AP Photo/Wilfredo Lee, File)

When lead defender Melisa McNeill gives her statement, she will likely emphasize that Cruz is a young adult with lifelong emotional and psychological problems. He allegedly suffered from fetal alcohol syndrome and abuse.

FLORIDA SCHOOL SHOOTING: JURY SELECTED FOR 2018 PARKLAND SHOOTER'S SENTENCING TRIAL

The case 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.

When jurors eventually get the case in the fall, they will vote 17 times, once for each of the victims, on whether to recommend capital punishment.

Every vote must be unanimous. A non-unanimous vote for any one of the victims means Cruz's sentence for that person would be life in prison. The jurors are told that to vote for the death penalty, the aggravating circumstances the prosecution has presented for the victim in question must, in their judgment, "outweigh" mitigating factors presented by the defense.

CLICK HERE TO GET THE FOX NEWS APP 

Regardless of the evidence, any juror can vote for life in prison out of mercy. During jury selection, the panelists said under oath that they are capable of voting for either sentence.

Fox News' Chip Bell contributed to this report, as well as The Associated Press.