Washington Township police said its department was working with other law enforcement agencies on an investigation outside Warren County.
Police issued the shelter-in-place order at 8:25 a.m. at all district school buildings.
The investigation is ongoing but the shelter-in-place orders were lifted at about 10 a.m.
"We have just been notified by the Washington Police Department that the Shelter-In-Place has been lifted. Everyone at the schools are safe and returning to our normal school environment," Warren Hills Regional High School posted on Facebook. "Thanks to our students and staff for their cooperation and patience."
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