A Canadian teenager accused of making a phony bomb threat to Princeton University last year has pleaded guilty to creating a false public alarm.

The 16-year-old boy entered his plea Friday, according to the Mercer County Prosecutor’s Office. It was made public on Tuesday.

The boy, who was 15 at the time, called the Princeton University Department of Public Safety on Sept. 19 and said he had placed improvised explosive devices in at least four locations, including the school’s art museum, chapel, main library and Nassau Hall. The campus was largely empty at the time.

The teen, whose name was not released due to his age, was sentenced to two years of probation.