This story has been updated.
ORANGEBURG, N.Y. -- Tappan Zee High School students were evacuated and sent home just before 10 a.m. Monday after an "unspecified threat" was found inside a bathroom, school officials said.
A Tappan Zee High School student discovered the message on a wall in a restroom that said "something bad would happen on 12/12," according to Superintendent Dr. Robert Pritchard.
Orangetown Police were then contacted, and the school's response plan was put into action. An emergency call went out to all parents and guardians advising the students were in the process of an early dismissal.
"After thorough investigation, this was determined to be an act of vandalism which turned out to be an unfounded threat," Pritchard said.
Pritchard said the decision to evacuate the building and cancel school for the day was made out of "an abundance of caution."
"With the help of Orangetown Police, the Rockland County Sheriff's Department and three canine units, the building was searched and cleared," Pritchard said. "While law enforcement officials are continuing their investigation, they have determined the building is safe and that students can return.
"We treat the safety and security of our staff and students as our most important responsibility. Please know that all threats to our schools, students and staff are taken seriously and investigated thoroughly."
After-school and evening activities will resume as regularly scheduled, and all classes will resume Tuesday on normal schedule.