Nikolas Cruz, with alleged links to a white supremacist group, was known for violent behavior and was expelled from the school prior to the attack. It was the second-deadliest shooting at a public school in US history.
According to a Broward County Sheriff's Office report, Cruz admitted to interrogating officers that he "began shooting students that he saw in the hallways and on school grounds" on Wednesday.
According to court documents, after being read his legal rights, "Cruz stated that he was the gunman who entered the school campus armed with a AR-15 and began shooting students that he saw in the hallways and on the school grounds."
Authorities have yet to determine a motive.
The FBI has also confirmed that it received a tip about Cruz last September. Agents were contacted by a Mississippi man named Ben Bennight after a user named Nikolas Cruz left a disturbing comment on his YouTube channel. The comment, which read "I'm going to be a professional school shooter," was investigated by the FBI but agents were unable to find any further information as to the time and location of the post.
Threatening behavior
Cruz, who had been expelled from the school last year for "disciplinary reasons" resulting from a fight with his ex-girlfriend's new boyfriend, was known for his threatening behavior among students and teachers. After his expulsion teachers were reportedly warned not to allow him onto school property with a backpack.
The shooter had few friends and many fellow students described him as a "loner" and a "weirdo." Authorities say Cruz had been receiving counseling at a local mental health clinic but stopped going to the clinic about a year ago.
Cruz had made repeated threats toward other students, and police are scouring a series of disturbing social media posts in which he posed with a gun and wrote about killing animals.
Cruz is originally from Long Island, New York, and moved to Broward County, Florida, with his parents and his brother. The boys became orphaned after their mother died of pneumonia late last year; their father died of a heart attack several years earlier. The boys had been in the care of a family friend, though Cruz moved in with a friend's family in late November citing unhappiness.
The family, which has not been named, knew that Cruz owned an AR-15 assault rifle and insisted that he keep it locked up, though he himself had a key to the safe.
On Wednesday afternoon, Cruz — outfitted with a gas mask, smoke grenades and his assault rifle — pulled the fire alarm, sending students pouring out into the hallway at which point he began shooting.
Cruz reportedly told investigators that he had decided to discard the AR-15 and vest during the commotion so as to blend in with the crowd. He was arrested shortly afterward off the school grounds without an incident.
Trump addresses Florida shooting
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Prayers and condolences
As has become routine in the wake of such shootings, politicians offered prayers and condolences to the victims' families and friends. US President Donald Trump made a point of stressing the shooter's mental health but avoided any mention of guns or gun laws during an address to the nation on Thursday.
The attack was the fifth-deadliest school shooting to ever be carried out in the country, and the second-deadliest shooting at a public school in US history.
Deadly mass shootings in the US
Mass shootings have become common tragedies in the US, where guns kill roughly 30,000 per year. From movie theaters to schools, mass shootings can occur at any place where large numbers of people are gathered.
Image: Getty Images/S. Platt
Ned Peppers Bar, Dayton
In the early hours of August 4, 2019, a man carrying a rifle opened fire at people outside a bar in Ohio, leaving nine people dead before police killed him. The man was wearing body armor and had additional magazines for the .223-caliber rifle. Police responded to the shooting within one minute; had they not, Mayor Nan Whaley said, "hundreds of people in the Oregon District could be dead today."
Image: picture-alliance/AP Photo/J. Minchillo
Walmart, El Paso
Several hours earlier, Patrick Wood Crusius was arrested on suspicion of killing 20 people and injuring 26. The suspect allegedly posted an online screed shortly before the shooting that echoed US President Donald Trump's anti-immigrant statements. He appeared to target people he believed to be immigrants from Mexico. Prosecutors said they'd treat the shooting as domestic terrorism.
Image: Reuters/C. Sanchez
Municipal Center, Virginia Beach
Mourners gathered for a vigil in response to a shooting at a municipal building in Virginia Beach on June 1, 2019. A longtime city employee opened fire, apparently indiscriminately, outside and inside the building before engaging in a battle with police, who ultimately shot and killed him, authorities said. Including the gunman, the death toll was 13.
Image: picture-alliance/AP Photo/P. Semansky
Borderline Bar & Grill, Thousand Oaks
In November 2018, a 28-year-old former Marine attacked a country dance bar outside Los Angeles, killing 12 people and wounding 10 others. The bar was holding a "College Night" and was packed with a young crowd. The gunman was found dead inside the bar, apparently he killed himself.
Image: picture-alliance/AP Photo/M. Terrill
Tree of Life Synagogue, Pittsburgh
Eleven worshipers were killed at the Tree of Life Synagogue in Pittsburgh in October 2018 while attending a baby naming ceremony. Six others were injured, including four police officers. The gunman is currently facing 29 criminal counts and could receive the death penalty. Police said he told officers that Jews were committing genocide and that
he wanted them all to die.
Image: picture-alliance/dpa/B. Wittpenn
Parkland, Florida
A 19-year-old former student of Marjory Stoneman Douglas High School in Parkland, Florida killed 17 of his fellow classmates in February 2018. For the first time in the US, survivors of a mass shooting came together to demand immediate action on gun control. The students founded March for our Lives, a nationwide student mass protest movement.
Image: picture-alliance/E.Rua
First Baptist Church, Sutherland Springs
A grudge against his in-laws led a 26-year-old man to attack a church in the small, tight-knit community of Sutherland Springs, Texas in November 2017. The shooter killed 26 people between the ages of 18 months and 72 years. The mass shooting prompted President Donald Trump to focus the issue of gun violence on mental health and away from gun ownership.
In the deadliest mass shooting in US history, concertgoers were targeted at a country music festival in Las Vegas in October 2017. The shooter, a 64-year-old man with no criminal record, attacked from a room in the nearby Mandalay Hotel, killing 59 people and wounding more than 400. Authorities found 23 guns in the shooter's room.
Image: picture-alliance/M. J. Sanchez
Pulse nightclub, Orlando
An Afghan-American with a deep hatred for homosexuals attacked a gay nightclub in the city of Orlando, Florida in June 2016. Using an AR-15 rifle, the gunman stormed the darkened hall and killed 50 partygoers. The shooting was condemned worldwide and brought attention to hate crimes against the gay community.
Image: Reuters/J. Young
Sandy Hook Elementary School, Newtown
The December 2012 shooting at Sandy Hook Elementary School in Newtown, Connecticut rocked the nation in its brutality. It was the first time children under the age of 8 had been directly targeted, with 20 of them dying. Mourning parents flew to Washington, DC to support President Barack Obama's background checks legislation. The law ultimately wasn't approved, despite an emotional national debate.
Image: AP
Century 16 Theater, Aurora
In July 2012, a gunman opened fire during a movie screening in Aurora, Colorado, causing chaos and confusion. In the aftermath, 14 people were killed and 50 were wounded. The assailant attacked moviegoers as they were watching the latest Batman movie, The Dark Knight Rises.
Image: picture-alliance/dpa
Virginia Tech University, Blacksburg
A student went on a shooting spree in a dorm and a class hall at Virginia Tech University campus in April 2007, leaving 32 people dead. The shooting turned the nation's attention to the National Rifle Association (NRA), the most powerful lobby group, which has fought to stop gun control laws.
Image: picture-alliance/dpa/T. Maury
Columbine High School, Littleton
The 1999 assault in Littleton, Colorado, was the first school shooting to shock the nation. Two disgruntled students walked into their high school and opened fire with automatic weapons, killing 13 people. The attack would later become the subject of a documentary by filmmaker Michael Moore, Bowling for Columbine, that examined the causes of gun violence in the US.
Image: picture-alliance/AP Photo/Jefferson County Sheriff's Department
