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 only challenges his sentence. It’s the nation’s deadliest mass shooting to go before a jury. A panel of seven men and five women, supported by 10 deputies, will hear the case, which is expected to last about four months. The trial was supposed to begin in 2020, but was delayed due to the COVID-19 pandemic and legal battles. Lead prosecutor Mike Sachs emphasized Cruz’s brutality as he stalked a three-story classroom building and fired his AR-15 semiautomatic rifle into hallways and classrooms. Cruz sometimes returned to wounded victims and killed them with a second volley of gunfire. The prosecutor 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 Nick. I will be the next school shooter of 2018. My target is at least 20 people with an AR-15 and some tracer rounds. It will be a big event and when you see me on the news, you will know who I am. You will all die. Oh yes, I can’t wait.” About 50 family members of the victims were in the courtroom, some couples holding hands. Some parents teared up as Satz described their children’s deaths. A mother, crying, got up and left. Others sat stoically, arms folded across their chests. It was unclear if anyone was present to support Cruz, who sat at the defense table between his attorneys. He mostly looked down at a piece of paper with a pencil in hand, but he didn’t seem to be writing. Sometimes he looked up to stare at Satz or the jury, looked at the audience or whispered to his lawyers. After Satz’s speech, Cruz’s attorneys announced they would not give an opening statement until it was time to present their case weeks from now. This is a rare and dangerous strategy because it gives Satz his only chance to speak before the jury examines gruesome evidence and hears testimony from survivors and the parents and spouses of the victims. When lead defense attorney Melisa McNeill gives her statement, she will likely emphasize that Cruz is a young adult with lifelong emotional and psychological problems who allegedly suffered from fetal alcohol syndrome and abuse. The February 14, 2018, shooting is the deadliest at trial in US history. Nine other gunmen who killed at least 17 people died during or shortly after their shootings, either by suicide or by police fire. The suspect in the 2019 killing of 23 people at a Walmart in El Paso, Texas, is awaiting trial. After opening statements, which are limited to 90 minutes each, the prosecution’s first witness will be called. They haven’t said who that will be. It is the first death penalty trial for Judge Elizabeth Scherer. When jurors finally get the case in the fall, they will vote 17 times, once for each of the victims, on whether to recommend the death penalty. Each vote must be unanimous. A non-unanimous vote for any of the victims means Cruz’s sentence for that person would be life in prison. Jurors are told that in order to vote for the death penalty, the aggravating circumstances presented by the prosecution for the victim in question must, in their judgment, “outweigh” the mitigating factors presented by the defense. Regardless of the evidence, any juror can vote for a life sentence out of mercy. During jury selection, panelists swore that they could vote for any proposal.