PARKLAND, Fla. _ The morning after the worst high school shooting in American history unfolded in the Broward County suburb of Parkland, parents, police, grief counselors and students at Marjory Stoneman Douglas High struggled to make sense of a massacre that killed 17 people and injured at least 15 more.
Once again, a community in grief asked itself familiar questions: How did everyone miss the signs that the suspected shooter was deeply troubled, especially given his ominous postings to social media? And what could be done to prevent such a tragedy from happening again?
Already, there were troubling signs that America's 18th school shooting this year may not be its last. Broward Sheriff Scott Israel said there had been "copycat threats" made at other schools on Thursday, including at Hallandale Beach High and North Broward Preparatory in Coconut Creek.
Students and staff were evacuated as the school was searched. The sheriff's office determined the threat was unfounded, but one deputy accidentally fired his gun and injured his leg while at the school. No one else was injured.
"We will respond to every threat," Israel said, vowing to charge those responsible.
Flanked by Florida Gov. Rick Scott, State Attorney General Pam Bondi and Broward Schools Superintendent Robert Runcie, Israel called for lawmakers to do more to help police keep guns away from those who have a mental illness _ a theme echoed by others.
"We want to make sure this never happens again," Scott told reporters outside Douglas High on Thursday. "How do we make sure individuals with mental illness never touch a gun?"
"We should not have disconnected youth wandering around our community," said Runcie, who called for "real funding" for mental health programs for young people.
Broward Mayor Beam Furr told the Miami Herald that Wednesday's shooting may have been prevented if police and teachers had acted on signs that the suspected shooter, Nikolas Cruz, was troubled.
"Somebody who has a mental health issue, how in the world they can get within a thousand feet of a gun, I don't know," Furr said, noting the photos and videos that the alleged shooter posted to social media, demonstrating his fascination with guns and stating his intent to shoot others.
But the even the FBI said it was unable to run down a threat allegedly posted to social media by Cruz, who had legally purchased the AR-15 semiautomatic assault rifle he allegedly used to carry out Wednesday's attack.
Rob Lasky, special agent in charge of the FBI's Miami office, said the agency had received a tip in 2017 about an ominous message posted to a YouTube video, allegedly by Cruz.
The message, Lasky said, read: "I'm going to be a professional school shooter."
Lasky said the commenter posted no information on the location or time. The FBI investigated the incident, he said, but "We were unable to identify the person who made the comment." The comment was posted by someone with the user name "nikolas cruz".
Though Scott, Israel and Runcie called for more funding for mental health programs, none said that Cruz has a mental illness.
But Furr told the Herald that Cruz had attended a local mental health clinic for about one year before he quit in the fall.
Furr said he did not know what mental health issue Cruz was getting help with, or the course of treatment he received. But he said Cruz may have stopped going to the clinic shortly before his adoptive mother, Lynda Cruz, died in November.
Adding more confusion to the enigmatic Cruz: A white nationalist group known for publicity seeking claimed Cruz as one of its members.
Jordan Jereb, the leader of a white nationalist militia group known as the Republic of Florida, which explicitly advocates for a whites-only nation, said Cruz attended meetings with the Clearwater cell of the group and traveled to Tampa with the group at least once.
Jereb, however, said he has never personally met Cruz and cannot attest to what extent Cruz was involved with ROF or how long he'd allegedly been a part of the group.
"I know with certainty he had something to do with us," he told the Herald.
Even though Cruz's since deleted social media posts did not include the usual exclamations of "white pride" associated with people who belong to extremist racist groups, Jereb said that didn't mean Cruz wasn't involved in one.
"A lot of people do this MAGA, Pepe the frog crap, but behind the scenes they're really going to our meetings," he said.
Speaking on National Public Radio early Thursday, Michael Udine, a Broward commissioner and former mayor of the city where the massacre unfolded, agreed that many missed the signs that Cruz was a potential danger.
"We have to be more vigilant," Udine said. "If this can happen in a city like Parkland, it can happen anywhere."
Across the country, America will mark the Parkland shooting with flags at half-staff after President Donald Trump issued a proclamation on Thursday ordering that the U.S. flag be flown at half-staff at the White House and all public buildings and grounds, military posts, naval stations and vessels and foreign embassies until sunset on Feb. 19.
In Broward, authorities revealed more details about Wednesday's bloody rampage at Douglas High, a school with about 3,000 students enrolled.
A law enforcement official said Cruz bought the assault rifle used in the deadly attack at a gun shop in Broward County in February of last year.
Cruz bought the .223-caliber rifle _ commonly referred to as an AR-15 _ after immediately clearing an instant background check by the gun shop owner through an FBI criminal database. Cruz did not have any criminal history.
"As far as I can tell, this was a clean sale," the law enforcement official told the Herald, who described the assault weapon as a "civilian version of a military rifle."
Cruz, a former student at Douglas High, was booked into the county jail Thursday morning after prosecutors charged him with 17 counts of premeditated murder.
Police had arrested Cruz on Wednesday after he attempted to blend in with students fleeing the scene. Cruz was wearing a military uniform from his JROTC class _ the U.S Army Junior Reserve Officer Training Corps _ according to two witnesses, and Broward Sheriff's Office deputies said they were able to track his movements using the school's video surveillance.
Zackary Walls, a senior at Douglas High and a JROTC member, said Cruz had been a member of the marksmen groups. He said the alleged gunman was able to slip out of the school unnoticed after the shooting, leaving his weapon and gas mask behind, because he was wearing his JROTC polo shirt, which he knew the group always wore on Wednesdays.
On Thursday, investigators and a stunned community began trying to reconstruct the events of Wednesday.
Investigators apparently were able to identify Cruz even as the shooting was occurring, according to one teacher at the school, who asked not to be identified. He said he had locked his students in a classroom and that he could hear a police radio outside the door. The teacher said he heard Cruz's name and a police officer say the suspected shooter might be headed toward the middle school nearby.
Broward officials also offered more details of the deadly rampage. While much remains unclear about the sequence of the shooting, Runcie said early Thursday that fire alarms at the school had been tripped by gun smoke from the assault weapon that Cruz allegedly used _ not by Cruz himself, as had been reported previously.
Runcie said Cruz had arrived on campus at the time of dismissal. "That is a fairly open time," Runcie said, explaining why Cruz apparently had no difficulty getting onto the school grounds. Cruz arrived in an Uber to the school, Javier Correoso, a company Public Affairs Manager confirmed to the Herald.
"We are assisting law enforcement authorities with the investigation," said, who declined to answer questions about how Cruz managed to conceal his weapons.
Runcie added that an armed school police officer was on campus when Cruz allegedly launched the attack, but that the officer "never encountered Cruz."
By the time the shooting was over, Broward Sheriff Scott Israel said, 12 people had died inside the school building, two died outside, one died on the street and two in an area hospital. The injured were taken to Broward Health North in Pompano Beach and Broward Health Medical Center in Fort Lauderdale.
Dr. Evan Boyer from Broward Health North said the hospital had received a total of nine patients, including the suspected shooter. Two patients later died at the hospital, Boyer said, and three remained hospitalized. Three others had been discharged home as of Thursday morning.
An additional six victims remain hospitalized at Broward Health Medical Center in Fort Lauderdale, said Dr. Michael Puente, trauma director for the hospital.
"Unfortunately, this is becoming routine," Puente said, referring to the 2017 mass shooting at Fort Lauderdale-Hollywood International Airport.
As the pain of the prior day's shooting settled in, grief counselors on Thursday morning fanned out to area parks, schools and libraries to help students, families and teachers cope with the tragedy.
Early Thursday, students and parents were greeted by two therapy dogs inside the Pines Trails Park Recreation Center.
Members of the Red Cross and local volunteers brought in tissues and snacks as some of the survivors and victims' loved ones fought back tears.
Waiting for her daughter outside the center, Heidi Feuerman said she was upset with herself for not believing her daughter soon enough.
About two months ago, Feuerman and her daughter, whose name was not given, stopped by the Dollar General where the shooting suspect worked. Feuerman remembered her daughter pointing him out.
"That's the kid," her daughter said. "If anybody's gonna be a school shooter, he's the one that's gonna be a school shooter."
Her daughter knew of Cruz's reputation as a loner and said he had a crush on her.
Feuerman told her not to be so quick to judge.
Now, Feuerman is just trying to be supportive of her kids, a daughter and son. As a mother, she said it's frustrating not to be able to relate to her kids' traumatic experience.
"I don't know what that feels like," she said.
Stephen Feuerman, Heidi's husband, said he's grown accustomed to shootings.
The silver lining?
"At least the support system is better than it ever was," he said.
(Herald Staff Writers Kyra Gurney, Alex Harris, Manny Navarro, Nicholas Nehamas, Nora Gamez Torres, Carli Teproff and Jay Weaver contributed to this report.)
