Massacre suspect put 'disturbing material' on social media - and was 'crazy about guns'
The gunman who allegedly killed at least 17 people at a Florida high school on Wednesday was a former student who posted disturbing material on social media and was "crazy about guns".
Police identified the suspect as Nikolas Cruz, a 19-year-old who had been expelled from Marjory Stoneman Douglas High School, in Parkland, about 72km north of Miami.
The suspect was wearing a gas mask and carrying smoke grenades, senator Bill Nelson, of Florida, told CNN.
Mr Nelson, who said that he had been briefed by the FBI, said the attacker had "set off the fire alarm so the kids would come pouring out of the classrooms into the hall.
"And there the carnage began."
He said he did not know if the gunman had used the smoke grenades.
But he said that he assumed that's why he had a gas mask on.
Frightened students ran out onto the streets as shots rang out, before SWAT team members swarmed the building.
Authorities later announced that they had taken the suspect into custody.
They took him to hospital after locating him in Coral Springs, a little over a kilometre-and-a-half away from the school.
He had surrendered to police without putting up a struggle, Broward County Sheriff Scott Israel said.
The Instagram page of the alleged shooter paints a picture of a man obsessed with guns and knives.
One of the more recent posts shows target practice, captioned: "Group therapy. Sometimes it really f***ing works."
Others show him posing proudly with his weapons, which include pistols and knives.
In one Instagram post, he seemingly asks followers for advice on a certain model of gun.
He also posed for selfies where he wore all black clothes and a balaclava.
One post about purchasing a shotgun reads: "I plan on getting this but I need more information on it so if someone could give advice on how much I'm spending and background cheeks [sic] please to god let me know."
Students at the school have confirmed the Instagram page is his.
One student, who escaped the shooting, wrote on Twitter: "He literally had an Instagram where he posted pictures of animals he killed gruesomely."
Jim Gard, a maths teacher, said that Cruz had been in his class last year.
"We were told last year that he wasn't allowed on campus with a backpack on him," Mr Gard told the 'Miami Herald'.
"There were problems with him last year threatening students."
However, Robert Runcie, the Broward County School district superintendent, told reporters that he was not aware of any concerns that had been raised about the student.
"We received no warnings," Mr Runcie said outside the school.
"Potentially there could have been signs out there.
"But we didn't have any warning or phone calls or threats that were made," he added.
One student, who did not want to be named, told TV station WSVN-7 that Cruz had said that he had guns at home and talked about using them.
"He's been a troubled kid," the student said.
"He's always had a certain amount of issues going on.
"He shot guns because he felt it gave him, I guess, an exhilarating feeling," he added.
Mr Israel said that the gunman had an AR-15 assault rifle and had "countless magazines".
"We already began to dissect his websites and the things on social media that he was on, and some of the things that came to mind are very, very disturbing," he said.
His Instagram account was taken down after the shooting.
But a number of screenshots were sent to various media outlets.
"Everything he posts is about weapons," one student told ABC News. "It's sick," they added.
Daniel Huerfano, a student who fled Wednesday's attack, said that he recognised Cruz from an Instagram photo in which Cruz had posed with a gun in front of his face.
Mr Huerfano recalled Cruz as a shy student and remembered seeing him walking around with his lunch bag.
"He was that weird kid that you see...like a loner," he added.