Police were called to the home of Nikolas Cruz at least twice by his own mother, over his disturbing behavior. The FBI has admitted to receiving a tip about the shooter last year.
US President Donald Trump was expected to meet with first responders to the recent deadly shooting at Marjory Stoneman Douglas High School in Parkland, Florida. He will also speak face-to-face with parents of the victims and some survivors, many of whom have responded to the attack by calling on the president to prevent further shootings.
Nikolas Cruz reportedly fired more than 100 shots at students and teachers on Wednesday, before being arrested at a nearby McDonald's. The 19-year-old was later charged with killing 17 people.
While investigators have yet to confirm a motive for the crime, Cruz was known to be violent and had links to a militant white supremacist group. The man had been expelled from the school for fighting with his ex-girlfriend's new boyfriend and for threats to his classmates and teachers.
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Cruz deemed not a danger
According to Buzzfeed, the authorities were called to Cruz's home 35 times because of the "out of control" behavior of the shooter and his younger brother Zachary. Their mother, Lynda, who passed away late last year, alerted police on more than one occasion that her sons were threatening her.
While both Nikolas and Zachary were reported by local officials as having mental health issues, in 2016 a therapist deemed Nikolas to be "no threat to anyone or himself at this present time."
The FBI has also admitted that it received a tip about Cruz last September. According to Mississippi resident Ben Bennight, he became concerned when a user named Nikolas Cruz left a comment on his YouTube channel saying "I'm going to be a professional school shooter," but the FBI were unable to determine the source of the post.
Cruz hailed a ride to Marjory Stoneman Douglas using Uber and arrived around 2:19 p.m. local time on Wednesday. He pulled the fire alarm, causing students and teachers to empty out of the classrooms, whereupon he opened fire.
The shooter then slipped into the crowd and fled to a local Walmart, and was later spotted by a policeman at a McDonald's.
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AR-15: 'Gold standard for mass murder'
The firearm used in the attack was a legally purchased AR-15 rifle, a semi-automatic weapon that was also used in the mass shootings at Sandy Hook Elementary School, at a movie theater in Colorado in 2012, and in San Bernardino, California, in 2015.
Originally designed for the US army and in production by Colt since the 1960s, the AR-15 is the most popular rifle in the United States, according to the National Rifle Association (NRA). The NRA has hailed the AR-15 as a reliable hunting weapon, though according to many hunting publications it is unhelpful in the pursuit of game as it is meant for close-range shooting.
A lawyer representing the families of Sandy Hook victims called the AR-15 the "gold standard for the mass murder of innocent civilians."