Police investigated threatening graffiti written on the wall of a boys' bathroom at Mt. Lebanon High School and determined no credible threat exists, according to the school district.

Students informed the administration this morning of messages written on the wall of a third-floor bathroom that said "11/19 Bomb" and "11/19 Shooting up the school."

The high school principal, Dr. Ron Davis, contacted Mt. Lebanon police, and officers termed the incident as institutional vandalism.

High school staff, parents and students also were informed of the graffiti message. Last month, graffiti also was scrawled on a sixth-floor bathroom wall. It said, "Bomb 10/26 u all die."

Dr. Davis has requested increased police presence around the school tomorrow, the school district said, and the staff has been asked to be more visible in hallways during class changes.

The entrance of the boy's restroom was under camera surveillance, and the tape will be released to the police, the district said, along with the names of students captured on the video entering the restroom prior to the discovery of the graffiti.

"We intend to prosecute the responsible party to the fullest extent possible with school consequences and criminal charges," Dr. Davis said.

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