The real problems started at least as early as middle school and quickly intensified. There were the vocal outbursts, disturbing drawings of stick figures with guns, constant disciplinary issues. There were threatening statements written on his homework, including a reference to killing President Barack Obama, saying he should be "burned alive and eaten."
Some teachers banned Nikolas Cruz from their classrooms at Westglades Middle School because of his erratic behavior. One teacher said he was barred from bringing a backpack to the school and security had to search him to ensure he didn't have weapons. Teachers were very concerned about him and were working to get him help.
"Looking in his eyes, he just looked like there was a problem," said a teacher who worked with Cruz in sixth grade. "His behavior in class wasn't constantly wrong, but every once in a while, it was. He would just spew something out of his mouth that was inappropriate."
Several teachers who knew Cruz in middle school said in interviews that he was an increasing behavioral challenge for the school system and appeared to be on a troublesome path. In the years before he would allegedly carry out one of the worst mass shootings at a school in U.S. history, Cruz faced a long string of escalating disciplinary measures throughout his academic career for insubordination, profanity, disruption, fighting and assault.
"I can say I was so uncomfortable around him, I did not want to be alone with him in my classroom," said one former teacher, who spoke on condition of anonymity because of the sensitivity of the topic. "That is how disruptive his behavior was."
In one school year, when he was in middle school, he racked up numerous infractions - including for a fight during the second week of school and continuing with a pattern of unruly behavior, insults and profanity, according to disciplinary records obtained by WPLG-Local 10, an ABC television affiliate in Miami that shared them with The Washington Post.
Teachers said that by eighth grade he was lashing out physically, randomly bumping other students in the hallways appearing to want to pick confrontations and fights and at times breaking out into profanity-laced tirades without any apparent trigger.
"Something would just upset him, and he would just do it and come to class and act out," said one teacher. His homework scrawls got more troublesome, including repeated tirades against American society, the comment about Obama and other writings teachers found alarming. He put a swastika on a test. He wrote about his intense interest in, and support for, guns.
His middle school and high school teachers referred him to individual and family counseling, the records show. They held parent conferences and called social workers. They sent him to in-school suspension, and they sent him off campus. For a time, they sent him to a school for emotionally disturbed youth.
Finally, after he was disciplined for an assault at Marjory Stoneman Douglas High School, they asked for an assessment of the threat he posed to his school, and ultimately he was expelled, about a year before he returned with a gun.
A person familiar with the records confirmed their authenticity, and interviews with teachers, administrators and those who knew Cruz - along with other records and accounts - show that he was well-known to school and mental health authorities and was entrenched in the process for getting students help rather than referring them to law enforcement.
It is unclear how complete the records are, and a Broward County schools spokeswoman said she could not comment on them due to "student privacy rules."
Instead of slipping through the cracks, it appears Cruz was the target of aggressive work to help put him on the right track. But it also appears he might have hit the limit of what could be done.
Teachers worked "very, very, very hard" to get Cruz to a school center that would help him address his issues, said the sixth-grade teacher, who noted that Cruz's now-deceased mother also understood his problems and wanted to get him help. But that process took years, the teacher said, and required loads of paperwork to back up Cruz's needs.
"We do, as teachers, everything that we possibly can to help these children, we truly do," the teacher said. "And it's a process. It's a big process. You have to have just so much information, which we did on him, we had so much."
Cruz's past interactions with the Broward County schools have come into increasing focus since the shooting Wednesday, when he took an Uber to his former high school, walked inside and allegedly started firing into a series of classrooms on two floors, killing 17 people, many of them teenagers. A school official - on notice that he could pose a danger - immediately raised concerns with other staff upon seeing him approach, but it was too late.
Howard Finkelstein, the Broward County public defender representing Cruz, has decried the shooting as avoidable, emphasizing all of the red flags that were missed in his client's life - including at school, in the mental health system and with the FBI, which failed to investigate a tip last month that Cruz seemed capable of violence and might shoot up a school.
"What we have gathered so far looks to us like this is a complete multi-system failure, that you had the school system failed . . . you had the mental health system failed," Finkelstein said. "When he went to purchase a gun, that system failed. . . . The FBI failed. When you look at it, this should never have happened."
Broward Schools Superintendent Robert Runcie declined to comment on Cruz's disciplinary past, but he said he is reviewing how Cruz's case was handled.
"There's always more that you could do, or could have done, but the fact is that there's more that the federal leadership and government could do," Runcie said in an interview Saturday. "They could put resources and make priority investments so that we can properly service these students who are disengaged or have mental health issues. That's what could have been done better."
Runcie said that while the district has a responsibility to ensure student safety, it cannot fall solely on a school district to handle mental illness.
"We need greater investments in mental health, social emotional services for our kids," Runcie said. "It's not just a school district problem. We can't solve every problem."
According to federal data, the district had about 580 counselors during the 2015-2016 school year, or about one counselor for every 462 students. The American School Counselor Association recommends one counselor for every 250 students.
While the school system falls short, it still has a far lower student to counselor ratio than most school districts in the United States.
Broward County schools once recorded more in-school arrests than any other Florida school system. But that harsh approach fell out of favor amid concerns that it was funneling too many young people - and particularly black and Hispanic students - into the juvenile justice system. Cruz is listed on official documents as being white.
In recent years, Broward schools became a leader in the national move toward a different kind of discipline - one that would not just punish students but would help them address the root causes of their misbehavior. Such policies aim to combat what is known as the "school to prison pipeline," giving teenagers a chance to stick with their education rather than get derailed, often permanently, by criminal charges.
Beginning in 2013, Broward stopped referring students to police for about a dozen infractions ranging from alcohol and drug use to bullying, harassment and assault. Instead, students who get in trouble for those infractions are offered an alternative program that emphasizes counseling, conflict resolution skills and referral to community social service agencies.
Jonathon Fishman, spokesman for the Broward Sheriff's Office, said last week that he had no record of deputies arresting Cruz before Wednesday.
As a result, Broward has seen a dramatic decline in the number of students who are arrested at school. In 2011-2012, Broward recorded 1,056 school-based arrests; by 2015-2016, that number had fallen 63 percent to just 392 school-based arrests.
The Obama administration held up Broward's transformed discipline system as a national model, inviting Runcie to speak about the district's approach in 2015.
Cruz's school records and interviews indicate that he was getting into trouble around the time of the policy shift.
One former middle school teacher said Cruz stood out in his mind among his problem students. He recalled "just him being very much a loner" and "erratic behaviors" that often disrupted his class. Sometimes, the former teacher said, Cruz would get up and start dancing around.
"At the time I never felt like he was a physical threat, but we knew that there was definitely deep issues," he said.
Teachers started pressing school administrators to have Cruz transferred to Cross Creek School, a K-12 public school for students with emotional and behavior disabilities that offers intensive psychiatric counseling. But one of Cruz's former teachers said the referral process into Cross Creek was agonizingly slow, complicated by a lack of classroom space and cumbersome state procedures for officially designating a student as a potential threat to himself or others.
"It's very hard to get a kid in there, very hard," the teacher said. "I don't know why, but I suspect it comes down to money. . . . So for three-fourths of the year, he went untreated at school."
In February 2014, Cruz was transferred to Cross Creek. In January 2016, after about two years at Cross Creek, he transferred to Douglas High School. It's not clear why he left Cross Creek, a small school tailored for his needs, for a sprawling comprehensive high school of more than 3,000 students.
At Douglas, Cruz got into trouble four times during the first half of the 2016-2017 school year - for fighting, insults and profanity. In September 2016, after a fight, Cruz was referred to social workers. A week later, the Department of Children and Families opened an investigation.
That agency found that in the aftermath of a breakup with his girlfriend, Cruz - who had been diagnosed with attention deficit/hyperactivity disorder (ADHD) and autism - was depressed and cutting himself, according to a confidential summary of the investigation obtained by The Post. Cruz was interested in buying a gun, the investigators found. Even so, they concluded he was a low risk for harm.
School officials, who knew Cruz well, appeared to challenge that notion, according to the report. They had noticed an abrupt change in Cruz's behavior after the breakup. The counselors had received reports not only that he was cutting himself, but also that he had drawn a Nazi symbol on his bookbag. School counselors raised concerns that it would be "premature" to conclude that Cruz was stable enough not to be hospitalized. A counselor who worked with Cruz at the time declined to comment when reached Saturday.
In January 2017, when Cruz was disciplined for an alleged assault, that triggered a call for a threat assessment, a formal process by which the school determines whether a student is dangerous and how that student should be supervised and supported.
Three weeks after the call for the threat assessment, Cruz transferred to an alternative high school. It's not clear whether the assessment was conducted, what its findings were or how those findings translated into any intervention.
The shooting has been "devastating" to Cruz's sixth-grade teacher, who said she has former students among the dead, and also has taught siblings of the victims.
"It's too hard. It's too much. It's awful what he did," she said, her voice breaking. "And the only reason I'm talking to you is because people need to know that it shouldn't be this hard to get someone the help they need."