His troubling behavior gave law enforcement plenty of opportunities to investigate and arrest him - and even take away his guns - long before he shot up Marjory Stoneman Douglas High School in Parkland last week, according to interviews with former South Florida prosecutors and legal experts.
In recent years, South Florida police detectives have arrested a slew of young men in unrelated cases who exhibited similar, troubling behavior on a variety of charges. Cops took them seriously.
It never happened with Cruz.
"There's no doubt there was a failure," former Miami-Dade prosecutor Marshall Dore Louis said of how law enforcement handled tips about Cruz. "The idea that they were aware of it and could do nothing is absurd. ... We can't let this happen again."
In the days since Florida's worst school shooting, Broward County Sheriff Scott Israel has repeatedly insisted that his deputies were legally "handcuffed" from arresting Cruz - and he is calling for more powers for police to deal with similar cases.
Comment: Did progressive 'racial equity' disciplinary policies play a part in the Florida school shooting?
It wasn't just BSO that failed to stop Cruz.
The FBI did not act on two strong tips, one of which involved Cruz posting on the internet that he planned to become a "professional school shooter." The Palm Beach Sheriff's Office was told Cruz had "put [a] gun to others' heads in the past." The Florida Department of Children and Families ruled him stable despite clear evidence of self-harm. And officials at Stoneman Douglas High, where Cruz killed 17 people on Valentine's Day, knew that he was cutting himself, threatening students and taking pictures with guns and that he may have "ingested gasoline ... in an attempt to commit suicide."
Those who could have stopped Cruz made "one mistake after another," said Andrew Pollack, whose daughter, Meadow, 18, was killed in the rampage.
The failures echo how law enforcement handled Florida's other recent deadly mass shooters, Omar Mateen and Esteban Santiago.
String of failures
One key misstep in Cruz's case came in February 2016, when a Broward deputy responded to a report that the teenager "planned to shoot up the school." An Instagram photo of a "juvenile" with a gun prompted the tip, according to a time line released by BSO on Thursday.
A Broward deputy determined that Cruz "possessed knives and a BB gun." But the information was not forwarded to a detective bureau or Broward's Intelligence Unit, which routinely monitors possible violent offenders who post online.
Rather, the information was sent to Stoneman Douglas' school resource officer, who is also a BSO deputy. Nothing happened.
BSO, on its Twitter account on Friday, said none of its interactions with Cruz "appeared arrestable under Florida law."
"The standard isn't whether that information itself was 'arrestable' but whether law enforcement had an obligation to investigate a violation of the law," said John Priovolos, a former Miami prosecutor. "A detective should have been assigned. Subpoenas should have been sent to Instagram to locate the IP address and verify it was Cruz.
"Cruz could have been arrested - maybe he would have been diverted to a mental-health court, but he would have been under some sort of supervision."
Even if a case couldn't have been made, the teen might have been placed squarely on the radar of police analysts who monitor potentially dangerous people who post online, Priovolos said.
"At the very least, the most capable intelligence detectives should have been monitoring him," Priovolos said.
Israel said BSO's handling of that tip is under internal investigation. The preliminary time line of BSO contact with Cruz is incomplete, meaning cops could have known more about him than they have so far disclosed. Israel did not release the time line until after appearing on a nationally televised town hall on CNN Wednesday.
"I don't know that the signs were missed," he told WPLG Channel 10 last Sunday in response to questions about BSO's handling of tips about Cruz. "This isn't science fiction. We're not allowed to arrest on what a person thinks about on pre-crimes. We're not allowed to Baker Act unless the person is an immediate threat to himself or someone else."
Israel continues to defend his department.
In an interview with the Herald Friday, he pointed out that BSO's Internal Affairs department is only investigating two of the tips it received concerning Cruz.
"In 90 percent [of the cases], we found no wrongdoing," Israel said. "We did what we needed to do."
But South Florida law enforcement already seems to be handling similar cases in a different manner.
On Friday, Miami-Dade Schools police arrested Krop High senior Sean Mesa for posting photos of himself with guns on social media. Improper display of a firearm is a misdemeanor in Florida. In addition, investigators said they found child pornography on his phone.
"The latest Snapchat photos have students and staff at Dr. Michael Krop Senior High alarmed and afraid," an arrest warrant stated.
At Cruz's former high school, authorities seemingly missed another opportunity to rein in the increasingly unstable young man.
In 2016, officials at Stoneman Douglas were told Cruz was violently and repeatedly threatening several classmates, according to a report in Buzzfeed News. Shortly after Cruz and his girlfriend broke up, he began sending messages to her friends on Instagram, blaming them for his romantic woes and threatening to kill them.
"I'm going to get you and I'm going to kill you because you took this person away from me. I'm going to kill your family," he said to Dana Craig, a one-time friend, in messages described to Buzzfeed.
Craig told Buzzfeed she reported the incident in writing to school security.
Then Cruz's ex began dating another student, Enea Sabadini. Cruz threatened Sabadini on several occasions in 2016 and 2017, calling him racial slurs and saying, "I have guns ... I will kill you," as well as sending a photo of at least six weapons laid out on his bed. Sabadini also reported Cruz's threats to the school, according to Buzzfeed.
Craig declined to comment to the Miami Herald on Friday. Sabadini could not be reached.
Cruz's threats to the teens could constitute aggravated cyberstalking, a felony, said Louis, the former Miami-Dade prosecutor. They could also violate state law against issuing written threats to kill.
"You have no right to say to somebody, 'I'm going to kill you,' " Louis said.
Richard Della Fera, a Miami defense attorney, agreed. And he said the lack of investigation into what was clearly a crime was troubling.
"If law enforcement saw the messages and could identify the person who was sending them, the ball got dropped when the investigation didn't go any further," said Della Fera, who has handled high-profile cases of people accused of posting violent material online.
Most important: Being charged with aggravated cyberstalking could have prevented Cruz from possessing the weapon he used to kill 17 people.
A condition of bond for felony stalking charges in Broward is the surrender of all firearms.
"He would be required to surrender any firearms that he had," Della Fera said. "He wouldn't have had the firearm."
And had he been convicted, Cruz's status as a registered felon would have further impeded his ability to purchase weapons under Florida law.
Asked about whether Broward schools could have done more to make sure Cruz's threats were investigated, Superintendent Robert Runcie said he had no "knowledge" of them.
Cruz could also have been charged federally.
In September, he wrote "I'm going to be a professional school shooter" on a YouTube channel. The comment would have been enough to charge Cruz with a threat of terrorism, a felony, according to an official in the U.S. Attorney's Office in Miami.
The comment was reported to the FBI. But a lackluster investigation did not identify Cruz as its author.
Federal agents also never followed up on a tip saying Cruz might "get into a school and just shoot the place up." The tip was made to an FBI call center in January.
"I know he's - he's going to explode," an unidentified caller told the FBI, according to a transcript first reported Friday by the Wall Street Journal.
Still, one of the survivors of the Parkland shooting believes the killing power of rifles like the AR-15 is to blame, not authorities.
"The main thing is the weapon itself caused an incredible amount of damage," Stoneman Douglas senior Emma Gonzalez, 18, said Friday. "I really resent when people are saying that the FBI [and law enforcement] is to blame for this. That's not true at all. [They] helped us get out of the building."
As the national debate on gun violence intensifies, policymakers and law enforcement in Florida are taking some action.
In Tallahassee, Gov. Rick Scott on Friday proposed barring those under 21 from buying firearms. He's also called for an investigation into how law enforcement missed the clear red flags on Cruz.
After the shooting, authorities embarked on a wave of arrests of students around the nation whose behavior was deemed threatening.
That's led civil rights watchdogs to express concern.
"We don't have to choose between unchecked gun violence on the one hand and turning our schools into the first step on the path to prison on the other," Howard Simon, executive director of the Florida chapter of the American Civil Liberties Union, said in a statement. "Funneling more kids out of classrooms and into jail cells is not the way to keep guns out of classrooms."
In the past, even when the evidence isn't overwhelming, police have made cases against loner types who might snap.
That's what Miami-Dade Police's Homeland Security Bureau did two years ago when it arrested Enrique Dominguez, who was posting disturbing images of himself dressed like the Joker, posing with combat-style knives.
His co-workers reported he pledged "allegiance to Allah," showed them ISIS execution videos and vowed to dress like the comic-book villain Joker before gunning down co-workers, according to a police report.
Dominguez was arrested on charges of aggravated assault. While Dominguez did not wind up spending significant time in jail, he got probation - with the threat of a judge sending him to prison if he didn't stay out of trouble.
"Even if there is not enough evidence at the time, you never know what further investigation will reveal," said Penny Brill, the recently retired head of the legal bureau at the Miami-Dade State Attorney's Office. "All of these threats should be investigated. You can't take them as jokes. You can't do that anymore."
Florida's current law governing written threats to kill or inflict bodily harm does have limits.
Case in point: Back in 2015, police arrested a teenager at Sarasota High who sent a series of public tweets that included "can't WAIT to shoot up my school" and "school getting shot up Tuesday," as well as an apology saying it was a joke.
An out-of-town watchdog group discovered the tweets and notified police, who rushed to the school to protect students. The boy was judged "delinquent" in juvenile court.
But an appeals court threw out the case in 2016, saying the law allowed only for a threat to a "specific victim or member of that person's family."
"Our efforts have been frustrated by current law, which covers threats directed towards individuals not institutions such as schools," Miami-Dade State Attorney Katherine Fernandez Rundle wrote to Florida lawmakers two days after the Parkland shooting in a letter supporting the broadening of the law.
A proposed bill in Florida's Legislature would, if passed, strike the "specific victim" wording in the law.
"Now is the time to amend the statute and give law enforcement the tools to ensure that no child feels unsafe at school because of online threats," she wrote.