CNN's FOIA of Broward County 911 records has produced a steady stream of scoops about Parkland, Fla. school shooter Nikolas Cruz fleshing out much of what is publicly known about Cruz's background and the various reports made warning the FBI and other authorities about his threatening behavior.

The report draws on one specific incident that unfolded in the immediate aftermath of Cruz's mother's death, when Cruz and his brother Zachary Cruz were living in Palm Beach County with Rocxanne Deschamps, a former neighbor who had been close to the family.

After one particularly violent outburst, Cruz said he was going to Dick's to pick up the AR-15 he had recently paid for, and that he would come back to attack her.

The police were warned by Deschamps, who told them about Cruz's violent past - that he'd "used a gun against people before" and had "put the gun to others' heads in the past" - but still they did nothing.

Cruz and his brother only lived with Deschamps for a few weeks before Nikolas was taken in by the Sneads, but Zachary - who reportedly suffered a breakdown following the shooting - stayed with Deschamps. Cruz had been staying with the Sneads, the parents of a friend, at the time of the massacre, deceiving them by claiming he didn't have a key to the gun safe where his AR-15 was kept in accordance with house rules.

As CNN reported earlier this week, Cruz had purchased 10 rifles in the year before his killing spree.

On the day after Thanksgiving, Cruz was at work at a Dollar Tree store. Rocxanne Deschamps' son, Rock, 22, called 911 to report that an "adopted 19-year-old son" had possibly hidden a "gun in the backyard," according to a dispatcher's notes. Rock Deschamps told law enforcement "there were no weapons allowed in the household," the report said. It's unclear from the record whether sheriff's deputies conducted a search. The incident was classified as "domestic unfounded," which means a deputy didn't find proof to back up the claims. The Palm Beach County Sheriff's Office was called again to the home four days later, when Rock said Cruz lashed out against the family that took him in, according to the Palm Beach deputy's report and dispatcher notes. The deputy went to a local park and found Cruz, who explained that he had misplaced a photo of his recently deceased mother and, emotionally distraught, began punching the wall. Cruz lost control the same way he had several times in the past at his mother's home in Parkland, Florida, when he had not taken his prescribed mood-altering medication, as CNN has previously reported based on Broward police documents. Rock interrupted Cruz and a fight broke out between them, according to the documents. Cruz left the home, and Rocxanne Deschamps called 911. She warned the police dispatcher that Cruz said "he was going to get his gun and come back," records show. She said Cruz had "bought a gun from Dick's last week and is now going to pick it up." Rocxanne Deschamps told the dispatcher that Cruz had "bought tons of ammo" and "has used a gun against ppl before," the notes said. "He has put the gun to others heads in the past." The Palm Beach sheriff's deputy who responded to the scene of the assault spoke to both young men, who "hugged and reconcile(d) their differences." Cruz "said he was sorry for losing his temper," the deputy wrote in his report. Rock Deschamps told the deputy that Cruz had been suffering significantly from the loss of his mother and that he didn't want him to go to jail, only to leave the house until he calmed down. He signed a form saying he refused to prosecute.

But perhaps the most chilling details of the report come at the very end, when a friend of the Cruz brothers describes Nikolas's anger at the fact that almost nobody had shown up for his adopted mother's funeral.

Cruz left Rocxanne Deschamps' home for good a short time later, according to her ex-fiancé Paul Gold, who was also a longtime former neighbor. While his younger brother Zachary remained at that home, Nik Cruz returned to Broward County to live with a friend, and stayed at the Pompano Beach home of James and Kimberly Snead. He took his guns with him, the Sneads said. Gold, who lived next door to the Cruz family in Parkland for years, told CNN that he drove Nik Cruz to his mother's funeral. The only people in attendance were the two sons, Gold, and Rocxanne Deschamps, he said. "The boy was stoic. Not a tear. Not an emotion. I asked him if he was upset. He said: 'I'm upset because nobody came, and nobody cares about my mother,'" Gold recalled. "I told him that his mother was loved by many, many people and they just couldn't make it, timing and whatnot. It was a complete lie. But I felt horrible. Here's this poor kid, and his mother dies, and not a soul shows up," Gold said. Gold told CNN he knew nothing of Cruz's guns. He now describes the teen as "a monster." The next time Palm Beach deputies visited the Deschamps home was on February 14, in the frantic hours after the school shooting. A deputy rushed Rock and his family out of the home, clearing the way for a bomb squad to arrive, according to a report.

The FBI have taken a lot of criticism, and many have demanded the resignation of FBI Director Christopher Wray, after it emerged that the bureau had received tips warning them about Cruz, but protocol wasn't followed and Cruz was never investigated.