PORTSMOUTH — Last Tuesday night, a janitor cleaning a bathroom stall at Portsmouth High School found a bomb threat scribbled on a wall. Portsmouth police and fire and the state police bomb squad responded with K-9 units to search the building for several hours.

Police Chief Lance Hebert said the message in a girl's bathroom stall said "there was a bomb in a certain locker."

"We made a clean sweep of the entire building and secured it," Chief Hebert said Friday morning. "We concluded it was a false alarm."

PHS Principal Robert Littlefield released this information to parents on Thursday evening to quell rumors.

"We opened school on Wednesday and our administrative team began an investigation to find the perpetrator of the prank. The matter is still under investigation," Mr. Littlefield wrote to parents. "We had absolutely no doubt our building was safe when we opened the doors to students on Wednesday morning."

Police are also investigating the threat. No one has been charged so far.