PARKLAND, Fla. (FOX 13) - A deadly shooting at a South Florida high school left 17 people dead, and questions as to how the shooting even occurred.
Former student and suspect shooter Nikolas Cruz was booked into Broward County Jail early Thursday morning, and has been charged with 17 counts of premeditated murder.
During a press conference, Broward County Sheriff said Cruz legally purchased an AR-15. The FBI received a tip in 2017 about a comment posted by a Youtube user saying, "I'm going to be a professional school shooter." At the time, the FBI could not identify the person who made the comment. A blogger who submitted a tip said it was Cruz.
The first victim has been identified as Aaron Feis, an assistant football coach at Marjory Stoneman Douglas High School.
The school's football team tweeted, "He selflessly shielded students from the shooter when he was shot. He died a hero and he will forever be in our hearts and memories."
Later Thursday morning, officials said the high school's athletic director and campus monitor, also died in the shooting. Their identities were not immediately provided.
"Those two heroes gave their lives for our kids and probably helped prevent this from being a worse tragedy," Superintendent Robert Runcie said during a press conference.
Runcie told FOX 13 Cruz was dropped off by an Uber driver around dismissal time Wednesday afternoon. He entered through what the school calls the "1200 building" which has freshmen students, and opened fire.
The gunshots and smoke set off the fire alarm, and Cruz proceeded to enter through the other two floors of the building, Runcie explained. At some point, he discarded his weapon and masked himself among students to escape the campus.
Two JROTC students, Zackary Walls and Colton Haab, tell FOX 13 News they were doing formations until 2:20 p.m. and decided, with 20 minutes left in the school day, to end practice.
"I am so happy I made that decision because where we do formation is 40 feet from where the shooter was," Zachary explained.
After hearing the fire alarm, he said he began leading students to the fire drill area, which was where the shooter was, but before they reached, he heard gunshots.
"I just put two and two together: fire drill and gunshots. And I was like, active shooter," Zachary said, who attended active shooter training with a local police department, and told the students to run back to the classroom.
"We were standing there with 2x4s ready to fight if we needed to," he added.
Colton and Zachary began grabbing Kevlar mats to create a barrier around the students. The students in the classroom survived.
Zachary said Cruz was in the JROTC program during his freshman year, and he believes Cruz wore a polo shirt from the program to blend in with students.
Authorities offered no immediate details about Cruz or his possible motive, except to say that he had been kicked out of the high school, which has about 3,000 students.
He has been described as a troubled teenager who posted disturbing material on social media before the shooting spree that killed 17 people and wounded more than a dozen others, according to a law enforcement official and former schoolmates.
Dakota Mutchler, a 17-year-old junior, said he used to be close friends with Cruz but hadn't seen him in more than a year following his expulsion from school.
"He started progressively getting a little more weird," Mutchler said.
Mutchler recalled Cruz posting on Instagram about killing animals and said he had talked about doing target practice in his backyard with a pellet gun.
"He started going after one of my friends, threatening her, and I cut him off from there," Mutchler said. "I think everyone had in their minds if anybody was going to do it, it was going to be him."
Runcie told reporters on Wednesday afternoon that he did not know of any threats posed by Cruz to the school.
Cruz's mother Lynda Cruz died of pneumonia in November, neighbors, friends and family members said, according to the Sun Sentinel. Cruz and her husband, who died of a heart attack several years ago, adopted Nikolas and his biological brother, Zachary, after the couple moved from Long Island in New York to Broward County.
The boys were left in the care of a family friend after their mother died, family member Barbara Kumbatovich, of Long Island, said.
Unhappy there, Nikolas Cruz asked to move in with a friend's family in northwest Broward. The family agreed and Cruz moved in around Thanksgiving. According to the family's lawyer, who did not identify them, they knew that Cruz owned the AR-15 but made him keep it locked up in a cabinet. He did have the key, however.
Jim Lewis said the family is devastated and didn't see this coming. They are cooperating with authorities, he said.
Victoria Olvera, a 17-year-old junior at the school, said Cruz was expelled last school year because he got into a fight with his ex-girlfriend's new boyfriend. She said he had been abusive to his girlfriend.
"I think everyone had in their minds if anybody was going to do it, it was going to be him," she said.
Cruz was taken into custody without a fight about an hour after the shooting in a residential neighborhood about a mile away. He had multiple magazines of ammunition, authorities said.
"It's catastrophic. There really are no words," said Broward County Sheriff Scott Israel.
Most of the fatalities were inside the building, though some victims were found fatally shot outside, the sheriff said.
The school will closed for the rest of the week.
Information from the Associated Press was used in this report.