(CNN)Nikolas Cruz massacred 17 people in February at his former high school in Florida. The question now is does he live or die?
Why Nikolas Cruz's death penalty trial would be complicated
Broward County prosecutors have said they plan to seek the death penalty despite his attorney's offer of a guilty plea in exchange for a life sentence.
If prosecutors seek the death penalty, Cruz will join a short list of mass shooting suspects who've faced their victims in court. Of the 10 deadliest shootings in recent US history, Cruz is the only one who was captured alive.
Some parents who lost their children at Marjory Stoneman Douglas High School have made their feelings known about a potential death penalty trial.
"I don't want to go through some lengthy trial that's going to be brutal. I want him to sit in a cell and rot for the rest of his life," said Andrew Pollack, whose daughter, Meadow, was one of the victims.
"Lethal injection is painless, it's too easy for the psychopath. I don't want it -- I want life."
Two other gunmen in recent high-profile attacks have also faced their victims in court -- with varied outcomes.
Last year, white supremacist Dylann Roof was condemned to death for killing nine black churchgoers in South Carolina. Two years prior, a Colorado judge handed a life sentence to James Holmes for the shooting deaths of 12 people at a movie theater.
Here's how Cruz's death penalty trial would unfold:
Death penalty trials involve an extensive process that painstakingly combs through graphic details of the shooting in court. No detail is too small, including the gunshots, autopsies and the killer's words.
Both sides relive the harrowing day through agonizing testimony from survivors and families. Attorneys bring in witnesses and hire experts to go through massive amounts of evidence.
Richard Hornsby, a criminal defense lawyer in Florida, said death penalty cases in the state involve a guilt phase to determine whether a suspect committed the crime or a lesser crime, and a second phase for the jury to determine the penalty.
"It takes at least two years for a death penalty case to even be ready for trial," he said.
That time frame can be extended if a defendant suffers from mental illness. He or she has to be examined and if found incompetent to stand trial, is sent to a state mental health hospital, which halts the case for the duration of treatment.
Howard Finkelstein, Cruz's public defender, has said if the case goes to trial, the jury will hear about the gunman's history of mental illness.
During death penalty trials, the defense focuses on proving mitigating circumstances to convince a jury not to impose the death penalty, Hornsby said. Such evidence can include diminished IQ and mental health issues, among others.
In some cases, death penalty trials are followed by lengthy appeals in which survivors return to court to face the killer all over again.
"When a victim's family takes this journey, they end up hollow-bodied for two decades, connected to the person that destroyed their life," Finkelstein said. "They hear over and over how the system failed to stop him."
Some Stoneman Douglas students are conflicted on the possibility of a death penalty trial.
Student leader Emma Gonzalez describes Cruz's potential death penalty trial as a "good" thing. Another student, Cameron Kasky, wants him to "rot forever" in prison instead.
Pollack does not refer to the gunman by name, and calls him 1800-1958 -- his criminal case number. If the death penalty trial proceeds, he said, he will not attend any hearings.
Instead of facing his daughter's killer in court, Pollack said he'll focus on ensuring her memory lives on through a program he's launched to ensure school safety.
A death penalty trial would deeply divide a grieving community, leading to fingerpointing between the school board, sheriff's office and state and federal governments, who've been accused of missing Cruz's many red flags before the shooting, Finkelstein said.
George Brauchler prosecuted the Colorado gunman in the 2012 movie theater attack.
During the trial, he described death penalty cases as so wrenching, they are like "months of a horrible roller coaster through the worst haunted house you can imagine."
Brauchler said he sought the death penalty after speaking with dozens of victims' family members. The jury spared the gunman's life and gave him life in prison instead, citing his history of mental illness.
In South Carolina, Roof's death penalty trial was so agonizing, during cross-examination, defense attorney David Bruck spoke only eight words when he approached one victim. "I am so sorry," he said. "I have no questions."
Cruz's public defender has made it clear that he's not looking forward to a death penalty trial.
Finkelstein is offering Cruz 's guilty plea in exchange for 34 life sentences without parole. That would take the death penalty trial off the table and spare the victims from reliving the nightmare during testimony, he said.
Finkelstein has said his client's guilt is not the question -- he's already confessed to the killing
"We have been up front, from the first 24 hours. He is guilty. He did it. It's the most awful crime in Broward County. He should go to prison for the rest of his life," Finkelstein said.
"There are people in the community who believe he should be locked up and the key should be thrown away. I happen to be one of those people."
Michael Satz, Broward County's prosecutor, declined to comment on whether he's open to a plea deal. He's previously said this is "certainly the type of case the death penalty was designed for."
Assistant State Attorney Shari Tate echoed the same sentiment this month.
"The state of Florida is not allowing Mr. Cruz to choose his own punishment for the murder of 17 people," Tate said.
Finkelstein said he's still hoping for a plea deal for his client, but quickly admits he knows "it will take divine intervention" for it to happen.
Cruz's next court appearance is a status hearing Friday.
In high-profile cases such as the Parkland shooting, there are no shortages of challenges for everyone involved.
And the jury is no exception, said Hornsby, the criminal defense lawyer.
"Since the state is seeking the death penalty, any juror who is opposed to the death penalty will automatically be stricken, meaning the selected jury panel will already be predisposed to consider the death penalty as a viable sentencing option before the first witness is called," he said.
Jury selection will likely take weeks because the trial may be moved to a different venue, according to Hornsby.
"Most difficult, you will have to find people who say they could be fair and impartial to the defendant given what they know about the Parkland murders," he said. "Good luck."
Florida's death penalty law requires the jury's decision to be unanimous. If one of the 12 jurors dissents, the defendant must be sentenced to life without parole, Hornsby said.
If a jury condemns Cruz to die, it'll take years for the execution to be carried out. At age 19, he'd be the youngest death row inmate in the state.