A person who was close to Nikolas Cruz called the FBI's tip line on Jan. 5 and provided information about Cruz's weapons and his erratic behavior, including his disturbing social media posts. The caller was concerned that Cruz could attack a school.
In a statement issued Friday, the agency acknowledged that the tip should have been shared with the FBI's Miami office and investigated, but it was not. The startling admission came as the agency was already facing criticism for its treatment of a tip about a YouTube comment posted by a "Nikolas Cruz" last year.
The FBI investigated the comment, which said "Im going to be a professional school shooter," but did not determine who made it.
FBI Director Christopher Wray said the agency was still reviewing its missteps on the January tip. He said he was "committed to getting to the bottom of what happened," as well as assessing the way the FBI responds to information from the public.
"We have spoken with victims and families and deeply regret the additional pain this causes all those affected by this horrific tragedy," Wray said in the statement.
Cruz has been charged with killing 17 people at Marjory Stoneman Douglas High School in Parkland, north of Miami.
Also Friday, mourners gathered for the first funeral for a shooting victim, packing the Star of David chapel to remember 14-year-old Alyssa Alhadeff. From outside the chapel, other mourners strained to hear the voices chanting Jewish prayers and remembering the star soccer player as having "the strongest personality." She was also remembered as a creative writer with a memorable smile.
A day earlier, details of Wednesday's attack began to emerge, showing how the assailant moved through the school in just minutes before escaping with the same students he had targeted.
Cruz jumped out of an Uber car and walked toward building 12 of the school, carrying a black duffel bag and a black backpack. A man inside spotted Cruz and knew he was a former student, a troubled kid.
He radioed a co-worker and within a minute heard gunshots.
The 19-year-old was wearing a maroon shirt, black pants and a black hat. The man, whose name was blacked out from a sheriff's affidavit, told detectives Cruz was moving "purposefully."
Cruz slipped into the building, entered a stairwell and extracted a rifle from his bag, authorities said. He shot into four rooms on the first floor — going back to spray bullets into two of the rooms a second time — then went upstairs and shot a single victim on the second floor.
He ran to the third floor, where according to a timeline released by the Broward County Sheriff's Office, three minutes passed before he dropped the rifle and backpack, ran back down the stairs and quickly blended in with panicked, fleeing students.
Florida State Sen. Bill Galvano, who visited the third floor, said authorities told him it appeared that Cruz tried to fire point-blank out the third-floor windows at students as they were leaving the school, but the high-impact windows did not shatter. Police told Galvano that it was not that difficult to open the windows.
"Thank God he didn't," Galvano said.
From the time Cruz entered the building until the time he left, only six minutes passed. During that brief time, he shot more than two dozen people, including 17 fatally.
After the rampage, he walked to a Wal-Mart and bought a drink at a Subway restaurant, then went to a McDonald's.
About 40 minutes later, a deputy saw him walking down a suburban South Florida street and grabbed him. He didn't put up a fight.
Among the dead: assistant football coach Aaron Feis, slain while shielding students from bullets; Joaquin Oliver, a student known for his unique look and who once dyed his hair bleach-blonde with tiger stripes; Alyssa Alhadeff, an avid soccer player and student; and 35-year-old geography teacher Scott Beigel, who helped students enter a locked classroom, only to be shot himself.
Among at least 1,000 people attending a candlelight vigil near the school Thursday night, some openly sobbed as the victims' names were read aloud. At one point, people began chanting, "No more guns! No more guns!"
Dressed in the school's red color, some held flowers while others wielded signs asking for action to fight school violence, including gun control.
"Kids don't need guns. No guns under 21," read one sign.
Ernest Rospierski, a teacher at the school, took several bracing breaths at the vigil as he talked to a reporter about the horror in the halls.
"Bang, bang, bang — all of a sudden the shooting stopped," he said. "I looked down. He was reloading. I yelled run. And then I ran behind as many kids as I could."
Authorities have not described any specific motive, except to say that Cruz had been kicked out of the high school, which has about 3,000 students and serves an affluent suburb where the median home price is nearly $600,000. Students who knew him described a volatile teenager whose strange behavior had caused others to end friendships.
Cruz was ordered held without bond Thursday at a brief court hearing. He wore an orange jumpsuit with his hands cuffed at his waist. His public defender did not contest the order and had her arm around Cruz during the short appearance. Afterward, she called him a "broken human being."
Wednesday's shooting was the 17th incident of gunfire at a U.S. school this year. Of these, one involved a suicide, two involved active shooters who killed students, two involved people killed in arguments and three involved people who were shot but survived. Nine involved no injuries at all.