FORT LAUDERDALE, Fla. (AP) — Florida school shooter Nikolas Cruz will be sentenced to life without parole for the 2018 murder of 17 people at Parkland’s Marjory Stoneman Douglas High School, after members of the jury said Thursday they could not unanimously agree that he should be executed.

The jury’s recommendation came after seven hours of deliberations over two days, ending a three-month trial that included graphic videos, photos and testimony from the massacre and its aftermath, heart-wrenching testimony from victims’ family members and a tour of the still blood-spattered building.

Under Florida law, a death sentence requires a unanimous vote on at least one count. Circuit Judge Elizabeth Scherer will formally issue the life sentences Nov. 1. Relatives, along with the students and teachers Cruz wounded, will be given the opportunity to speak at the sentencing hearing.

“We are beyond disappointed with the outcome today,” Lori Alhadeff, whose daughter, Alyssa, was killed, said at a news conference after the jury’s decision was announced.

“This should have been the death penalty, 100%," she said. "Seventeen people were brutally murdered on Feb. 14, 2018. I sent my daughter to school and she was shot eight times.

"I am so beyond disappointed and frustrated with this outcome. I cannot understand. I just don’t understand.”

Cruz, his hair unkempt, largely sat hunched over and stared at the table as the jury’s recommendations were read. Rumblings grew from the family section — packed with about three dozen parents, spouses and other relatives of the victims — as life sentences were announced. Many shook their heads, looked angry or covered their eyes. Some parents sobbed as they left court.

Cruz, 24, pleaded guilty a year ago to murdering 14 students and three staff members and wounding 17 others on Feb. 14, 2018. Cruz said he chose Valentine’s Day to make it impossible for Stoneman Douglas students to celebrate the holiday ever again.

The massacre is the deadliest mass shooting that has ever gone to trial in the U.S. Nine other people in the U.S. who fatally shot at least 17 people died during or immediately after their attacks by suicide or police gunfire. The suspect in the 2019 massacre of 23 at an El Paso, Texas, Walmart is awaiting trial.

Stand With Parkland released a statement shortly after the verdict that said:

“Today’s ruling was yet another gut punch for so many of us who devastatingly lost our loved ones on that tragic Valentine’s Day at Marjory Stoneman Douglas High School,” said Tony Montalto, father of Gina Montalto and President of Stand with Parkland. “17 beautiful lives were cut short, by murder, and the monster that killed them gets to live to see another day. While this sentence fails to punish the perpetrator to the fullest extent of the law — it will not stop our mission to effect positive change at a federal, state and local level to prevent school shooting tragedies from shattering other American families.”

Polk County Sheriff Grady Judd, speaking to reporters about the shooting of one of his deputies, was asked at a news conference about the Cruz verdict.

Judd, referencing his time on the board that investigated the shootings, said he was neither surprised nor shocked about the verdict. But he made his feelings clear about Cruz.

"If there's ever been anyone on the face of the earth that deserved the death penalty, it was that evil, violent, murdering piece of trash that massacred those children," he said.

"If you can't get the death penalty for that in Broward County, that's not a safe county to live in," he said.

Tony Montalto, father of Gina Montalto, said: “How can the mitigating factors make this shooter, who they recognized committed this terrible act — acts, plural — shooting, some victims more than once on a pass, pressing the barrel of his weapon to my daughter’s chest — that doesn’t outweigh that poor little what’s-his-name had a tough upbringing?”

WATCH: Polk County Sheriff Grady Judd talks about Nikolas Cruz verdict

Lead prosecutor Mike Satz kept his case simple for the seven-man, five-woman jury. He focused on Cruz’s eight months of planning, the seven minutes he stalked the halls of a three-story classroom building — firing 140 shots with an AR-15-style semi-automatic rifle — and his escape.

He played security videos of the shooting and showed gruesome crime scene and autopsy photos. Teachers and students testified about watching others die. He took the jury to the fenced-off building, which remains blood-stained and bullet-pocked, gave tearful and angry statements.

Cruz’s lead attorney Melisa McNeill and her team never questioned the horror he inflicted, but focused on their belief that his birth mother’s heavy drinking during pregnancy left him with fetal alcohol spectrum disorder. Their experts said his bizarre, troubling and sometimes violent behavior starting at age 2 was misdiagnosed as attention-deficit/hyperactivity disorder, meaning he never got the proper treatment. That left his widowed adoptive mother overwhelmed, they said.

The defense cut its case short, calling only about 25 of the 80 witnesses they said would testify. They never brought up Cruz’s high school years or called his younger half-brother, Zachary, whom they accused of bullying.

In rebuttal, Satz and his team contended that Cruz did not suffer from fetal alcohol damage but has antisocial personality disorder — in lay terms, he’s a sociopath. Their witnesses said Cruz faked brain damage during testing and that he was capable of controlling his actions, but chose not to. For example, they pointed to his employment as a cashier at a discount store where he never had any disciplinary issues.

Prosecutors also played numerous video recordings of Cruz discussing the crime with their mental health experts where he talked about his planning and motivation.

The defense alleged on cross-examination that Cruz was sexually molested and raped by a 12-year-old neighbor when he was 9.

Florida Gov. Ron DeSantis agreed with the families, saying it “stings” that Cruz will not receive the death penalty.

In a case like this, “where you’re massacring those students with premeditation in utter disregard for basic humanity ... I just don’t think anything else is appropriate except a capital sentence,” DeSantis said.

Robert Schentrup’s sister, Carmen, was one of the students killed. He lives in Orlando and works for an organization to prevent gun violence.

Just before the jury’s decision came down, he told us he preferred his sister’s killer get life in prison.

“It’s actually more expensive than putting someone away for life, but that it is, in my opinion, morally wrong because an eye or an eye is not the best way to lead out justice," he said.

Schentrup decided it was best to not be at the trial.

“It has really been a lot brought back up, and I know that was something that could happen, and I really wanted to make sure I was taking steps to ground my own safety and mental health," he said.