BROOKVILLE, N.Y. (CBSNewYork) – One day before graduation, a threatening letter was found on a Long Island University campus.

Nassau County police said the letter was found in a dormitory bathroom on the LUI Post campus in Brookville.

The writer threatened to stalk and shoot people and “make a homemade bomb and blow the (expletive) roof off” the dorm after someone allegedly messed up his or her room.

“It’ll be like 9/11 and the Boston Bombing all over again,” the letter read in part.

The school’s public safety department was notified and then contacted Old Brookville and Nassau County police.

“This afternoon, Public Safety was informed of a potentially concerning letter found at Brookville Hall. Public Safety immediately dispatched units, informed the Old Brookville Police Department, and began an investigation into the incident,” school administrators said in an email to students. “At this time, there are no specific threats against any individual. Public Safety will maintain a state of vigilance to ensure the safety of all members of the community.”

Nassau County police said they spoke with dormitory residents and do not believe the threat to be credible.

School administrators said commencement is the biggest event of the year and tight security measures were already in place.