Broward County school officials lifted the lockdown Wednesday afternoon after several hours and said students would be dismissed normally. They said more police officers would be present, but didn't elaborate on why the threat had diminished.
The lockdown began after a woman called a radio station and said her husband might go to a school and start shooting.
Police are still investigating the threat and no suspects have been identified.
The radio station then found an earlier e-mail, possibly from the man, saying "something big was going to happen," possibly at a post office or a school.