E-mail and phone tips to a local radio station about a threat of violence directed at an unnamed Broward County school were credible enough to lock down the nation's sixth-largest school district for several hours Wednesday.
The tips launched law enforcement into an extended scramble to find the source of the threats that unnerved thousands of parents and left students locked inside their classrooms all day.
Late Wednesday, police did not have anyone in custody. Instead of dusting for prints, they were looking at "digital fingerprints" to lift clues to the source of the threats. Investigators said they had ruled out a hoax, a terrorist attack, or a disgruntled current or former school district employee.
Pembroke Pines Police Capt. Daniel Rakofsky said an unidentified woman called Pompano Beach-based radio station WFTL 850 AM, at 8:50 a.m. Wednesday, to say her husband was going to a school in Pembroke Pines, where he would start shooting.
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That prompted the city police force to lock down schools there, Rakofsky said.
After alerting law enforcement, radio station management went through e-mails and discovered one sent early Wednesday morning that also mentioned a threat, but to Broward County, he said. That e-mail indicated "something big was going to happen" involving county government buildings.
By 11 a.m., the school district expanded its "code red" lockdown throughout the district, while several private schools and local libraries also locked their doors. No other county buildings were closed, though security was increased.
Federal, state and local police agencies were examining the "digital fingerprint" of the caller and e-mail writer to figure out who sent them, said Rakofsky. They were concentrating on the IP address of the e-mail and cell phone records.
If an arrest is made, it was unclear what charges would apply.
"We have to determine exactly what was done, how it was done, and that will determine what crime has been committed," said Rakofsky.
Officials at WFTL could not be reached for comment. The station is home to conservative talk show host Joyce Kaufman, who was just hired to be U.S. Rep.-elect Allen West's chief of staff. Police would not say if the threats were related to Kaufman.
While still trying to figure out who made the threats, authorities determined by 1:15 p.m. that they were no longer credible enough to continue the lockdown. Students left on time, but all after-school activities were canceled.
The move affected all 230,000 Broward County public school students, faculty members and employees in 275 buildings.
Information about the Broward lockdown was circulated to dozens of schools in southern Palm Beach County as a precaution, but no schools there were affected, according to Palm Beach County School District spokesman Nat Harrington.
In Broward, worried parents stayed glued to news reports while school officials launched a rumor-control hotline and posted updates on the district's website.
At Lakeside Elementary School in Pembroke Pines, Cessilia Triana was among 40 anxious people who wanted to pick up children at 1:30 p.m., 20 minutes earlier than usual.
Triana was upset because, she said, "A SWAT officer told me I had to be 100 yards away from the school [entrance] or I was going to be arrested."
Her 5-year-old son was still in his kindergarten class, as were the children of the parents near the driveway at 900 NW 136th Street where Triana was cooling her heels.
"I'm freaking out," the worried mom said.
Kids weren't always told what was happening, but older, high school students found out and were texting and tweeting from classes.
To pass the time, some seniors at Weston's Cypress Bay High School watched movies, while others just read books or did nothing once that day's lesson was finished.
Diego Castillo's instructor at Dillard High covered a window at the doorway to prevent people from looking into the classroom. Castillo, 18, remembered another significant lockdown in 2008, when Amanda Collette was killed by classmate Teah Wimberly in a hallway between classes.
"So I was wondering if there was anything going on at my school," Castillo said. He needn't have worried.
"No students went wild or anything. It was all calm and cool," he said. "We kept our composure, and we stayed safe."