The gunman will spend life in prison, but relatives and prosecutors had sought the death penalty.
The gunman who killed 17 people at Marjory Stoneman Douglas High School in Parkland, Florida, has been spared the death penalty.
A jury recommended that the defendant, 24, should instead spend the rest of his life in prison for the 14 February, 2018 shooting.
Family members of victims were visibly upset and angry as the decision was read out in court.
A sentencing hearing has been set for 1 November.
The gunman, Nikolas Cruz, pleaded guilty to the murders in October last year. It was the deadliest mass shooting case ever to reach a jury trial in the US.
The verdict sparing him from capital punishment was described as “unreal” and “wrong” by relatives of those killed at a press conference afterwards.
“I could not be more disappointed in what happened today,” said Fred Guttenberg, whose 14-year-old daughter Jaime was among the students killed.
“I’m stunned. I’m devastated,” he said. “There are 17 victims that did not receive justice today. This jury failed our families today.”
The jury’s decision was also a blow for prosecutors, who had repeatedly sought to prove that the crimes were “cold, calculated and premeditated” and met Florida’s definition of “aggravating factors” that warrant the death penalty.
A unanimous decision would have been needed to issue a death sentence.
As each of 17 counts was read out in court, it emerged that while jurors agreed there were factors that would warrant the death penalty, at least one juror believed there were also “mitigating factors” that instead warranted life in prison.
Distress was visible on the faces of many of the family members gathered in court. Tony Montalto – who lost his daughter, Gina, in the attack – shook his head repeatedly. His arm was around his wife, Jennifer, who dropped her head on his shoulder as the count related to Gina was read out.
Other family members could be seen crying quietly. Corey Hixon – whose father Christopher Hixon died in the attack – stood up and left the room as soon he heard the jury’s recommendation for a life sentence instead of death.
Speaking to reporters after the hearing, Ilan Alhadeff, whose daughter Alyssa was killed, said the gunman was “not a human being – he’s an animal.”
“I pray that animal suffers every day of his life in jail,” he said. “And that he has a short life.”
Gordon Weekes, the Broward County public defender in charge of the defence team, called on the public to “respect the process” that led to the verdict.
He added that he believes the decision marks a “solemn opportunity to reflect on the healing that is necessary for this community”.
Both Florida’s Republican governor, Ron DeSantis, and his electoral opponent, Democrat Charlie Crist, said they believed the gunman should have received the death penalty.
“I just don’t think anything else is appropriate except a capital sentence in this case,” Mr DeSantis said.
The gunman was aged 19 when he walked into Marjory Stoneman Douglas High School and opened fire using a legally bought AR-15 rifle. Within four minutes, 34 people had been shot. Seventeen of them – 14 students and three staff members – were killed. The attack remains one of the deadliest school shootings in US history.
In the chaos that ensued, the gunman managed to escape the crime scene by blending in with students, and lingered in the area after buying a soft drink at a nearby fast-food restaurant. Soon after, he was arrested by police about two miles (3.2km) from the school.
In the aftermath of the killings, prosecutors presented evidence that the attack had been premeditated. The gunman researched past mass killings, and posted online comments in which he said he would show “no mercy”. In one video, taken days before the shooting, the gunman said he planned to be the “next school shooter” of the year and that his goal was to murder at least 20 people.
The gunman’s lawyers sought to portray him as mentally ill, a young man psychologically shattered by a difficult childhood in which he was “poisoned” by his mother’s drinking and substance abuse.
The shooting energised the already divisive US conversation about guns, and prompted a wave of youth-led activism.
In the days after the tragedy, a group of surviving students – including Cameron Kasky, David Hogg, X Gonzalez and Sarah Chadwick – called on social media for stricter gun control laws and the right to be able to go to school without the fear of being killed.
Just six weeks after the attack, an estimated 800,000 people attended the “March for Our Lives” rally against gun violence in Washington DC.
The organisation continues to campaign for policy aims such as more regulation and control of firearms and holding the gun lobby “accountable”.
But its legislative goals, such as a ban on assault weapons and high-capacity magazines, have proved elusive.