According to the University's Department of Public Safety, the sound was caused by a hammer hitting a chisel during a repair on Nassau Hall.
While conducting its follow-up investigation, DPS learned that about 20 minutes before the call was made Tuesday evening, a maintenance worker was using a hammer and chisel to fix a door on Nassau Hall.
The worker made the repair and left the building before an employee inside the building called to report the sound to DPS.
DPS determined that it is highly likely that the sound of the hammer hitting the chisel was interpreted as a gunshot.
"We take all reports from our community extremely seriously," said Paul Ominsky, DPS executive director. "The response and collaboration from my team, the Princeton Police Department and others throughout this incident were outstanding."
