SHRUB OAK, N.Y. - Lakeland High School was evacuated around 11 a.m. Thursday, after a threatening message was discovered in a school bathroom, according to police and school officials.

Students returned to class around 12:05 p.m., but the Yorktown Police Department is still investigating the written threat, said Chief Robert Noble.

“We consider it an open investigation and if we discover who committed the act, felony charges will be lodged against them,” Noble said.

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Noble did not disclose the message, but said the threat was “non-specific” and police did not believe it was credible. However, he said, the district took "proper precaution" in evacuating the school.

"The threat would certainly cause most to be concerned for their safety," Noble said.

On its Facebook page, the police department said that “at no time” were students and staff in danger.

*Around 1:50 p.m., another threatening message was discovered in a bathroom at Walter Panas High School in Cortlandt, the district's other high school.

Because the threat was discovered around normal dismissal time, Walter Panas students were evacuated to the school bus area. 

Westchester County and New York State police finished a sweep of the school around 2:45 p.m. and determined it was safe to return to normal activities, said James VanDevelde, communications director for the district.

Like the other threat, the one discovered in Walter Panas was also “non-specific” and considered “not credible,” VanDevelde said. He did not disclose the message, but said it was different from the one discovered at Lakeland High School.

*Editor's Note: This story was updated after another threatening message was discovered at Walter Panas High School.