Long Beach schools will return to normal operations Wednesday, officials said Tuesday evening, several hours after the district’s high school was ordered locked down as police investigated a threat, but found nothing.

“The police have concluded their investigation at the High School and we are preparing to return to regular operations tomorrow,” Superintendent David Weiss said in a notice sent to parents Tuesday night.

It capped off a day of anxiety as police said an unspecified threat against the school was called into police at 11:47 a.m., prompting a police response.

Weiss posted a notice on the district’s website once the lockdown at the high school was imposed.

“Due to a threat made against the high school both the Nassau County Police Department and Long Beach City Police Department are on scene conducting an investigation,” Weiss said in a message posted on the Long Beach Public Schools website after the threat was made. “As a result, the high school is on lockdown. Out of an abundance of caution, all other buildings in the district are operating on a lockout status.”

Weiss said that “the safety and well-being of our students and staff is our top priority. We are taking all the necessary precautions and everyone is safe.”

School district representatives during the day referred all inquiries about the lockdown to Nassau police.

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After the lockdown was lifted, police said there was a “controlled exit of students.”

Weiss said in the second notice that the high school campus was closed Tuesday evening and that the lockout at the other buildings was lifted with dismissal of students at the end of the school day.

“We thank law enforcement personnel for their prompt response,” the note continued. “We apologize for any inconvenience our emergency procedures caused. Thank you for your understanding.”

With Nicole Fuller