Prosecutors in the Parkland school massacre case are calling for law enforcement to interview a juror who said she felt threatened by another juror during deliberations over Nikolas Cruz's punishment for the 2018 South Florida killings, a court filing reads.

The request comes after a jury Thursday kept Cruz from getting the death penalty, recommending when it did not unanimously agree Cruz should get capital punishment.

The state's new motion asks Broward Circuit Judge Elizabeth Scherer to compel law enforcement officers to interview the juror who reported feeling threatened. It does not identify the juror and does not indicate which sentence the juror supported.

The juror called prosecutors Thursday after the jurors' decision was read in court, according to the court filing obtained by CNN.

"Juror X spoke to a support staff member and informed the support staff member that during deliberations she received what she perceived to be a threat from a fellow juror while in the jury room," the filing says. "The State did not call Juror X back and instead, filed a Notice to the Court."

It is not clear whether Scherer will comply with that prosecution request. A hearing for the state's motion is set for 1:30 p.m. Friday, according to the county's court docket.

The motion is the latest indication of behind-the-scenes tension among the jury in a , whose outcome . On Thursday, a juror wrote a letter to the judge calling the deliberations "tense," saying some jurors became "extremely unhappy" when she mentioned she'd vote for life in prison. And in an interview, the jury foreman described disagreement among the panel, saying three of the 12 jurors opposed the death penalty in this case.

It is not clear whether the juror who reported the perceived threat is the same juror who wrote the letter to the judge.

Cruz had admitted to killing 14 students and three school staff members and injuring 17 others in the Valentine's Day 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida. Because Cruz pleaded guilty to all counts -- 17 counts of murder and 17 counts of attempted murder -- the trial phase was skipped and the court went directly to the sentencing phase.

As the jury's sentencing was read aloud in court Thursday, jurors stared straight ahead or gazed into their laps.

Jurors didn't look in the direction of the visibly emotional victims' families in attendance, many of whom hoped the shooter would receive the death penalty and later over Thursday's decision.

The judge is expected to issue the gunman's formal sentence on November 1 and by law is unable to deviate from the jury's recommendation of life.

DELIBERATIONS WERE 'TENSE,' A JUROR WROTE IN LETTER TO JUDGE

The deliberations became "tense," a juror wrote in the handwritten letter addressed to Scherer. The juror, who voted against the death penalty for Cruz, wrote to the judge that "some jurors became extremely unhappy once I mentioned that I would vote for life."

In the letter, the juror also denied allegations that she made up her mind to vote for life in prison before the trial began, saying she heard other jurors had made such accusations about her.

Of the 12 jurors, three voted against recommending the death sentence, jury foreman Benjamin Thomas told , adding, "I don't like how it turned out, but ... that's how the jury system works."

"There was one with a hard 'no' -- she couldn't do it. And there was another two that ended up voting the same way," Thomas said. The woman who was against it "didn't believe, because he was mentally ill, he should get the death penalty," Thomas said.

To recommend death, the jury would have needed to unanimously agree that aggravating factors -- reasons the prosecution said he should be put to death -- outweighed mitigating circumstances, or aspects of Cruz's life and upbringing the defence said warranted only life in prison.

The jury did not unanimously agree on this, meaning Cruz must be sentenced to life in prison without possibility of parole.

During the sentencing trial, prosecutors argued that any mitigating factors were overshadowed by what they described as Cruz's exceptionally cruel and heinous acts. They presented detailed evidence to support their claims that Cruz carefully planned and premeditated the attack. The prosecution rested their case after jurors toured the where the massacre happened.

Cruz's attorneys the shooter as a severely "broken" person who suffers from a number of mental and developmental issues that were not adequately treated when he was growing up.

'YET ANOTHER GUT PUNCH' FOR DEVASTATED FAMILIES

Victims' loved ones were after hearing the verdict, and many denounced the decision as inadequate punishment given the extraordinary losses they have suffered.

The 14 slain students were: Alyssa Alhadeff, 14; Martin Duque Anguiano, 14; Nicholas Dworet, 17; Jaime Guttenberg, 14; Luke Hoyer, 15; Cara Loughran, 14; Gina Montalto, 14; Joaquin Oliver, 17; Alaina Petty, 14; Meadow Pollack, 18; Helena Ramsay, 17; Alex Schachter, 14; Carmen Schentrup, 16; and Peter Wang, 14.

Geography teacher Scott Beigel, 35; wrestling coach Chris Hixon, 49; and assistant football coach Aaron Feis, 37, were also killed -- each while running toward danger or trying to help students to safety.

Alyssa's mother told CNN Friday she was shocked by how quickly the jury's decision came -- on the second day of deliberations.

"I just would have wanted the jurors to spend more time going through the evidence, really trying to convince ... all 12 jurors that this animal should be getting the death penalty," Lori Alhadeff said.

"They had time, and they really should have gone through the evidence. It almost makes me feel like that there was somebody that already had this notion ... that they were never going to give the death penalty," Alhadeff said.

Hixon's widow, Debra Hixon, told CNN Thursday that when she realized the killer wouldn't receive the death penalty, she felt like she had been punched in the chest.

"What hurts the most is that there is a belief that any mitigating circumstances could outweigh what he did to our loved ones," Hixon said, adding, "Because the way it comes out is that his life has more value than those that were murdered."

Public defender Gordon Weekes urged the community to respect the jury's decision.

"This day is not a day of celebration, but a day of solemn acknowledgment, and a solemn opportunity to reflect on the healing that is necessary for this community," he told reporters.

But several families were insistent that the jury's decision does not deliver them peace. The mother of Helena Ramsay, a 17-year-old senior, also denounced the jury's recommendation.

"After spending months and months listening, and hearing testimonies, and looking at the murderer -- his composure -- I believe justice was not done," Anne Ramsay said. "The wrong verdict was given out today."

Some relatives also continued their pleas for gun policy reform to prevent the growing specter of gun violence in American schools, including Gina Montalto's father.

"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," Tony Montalto said.