A ninth-grader at Mount Sinai High School is facing charges after allegedly making threats against his school.

A 15-year-old boy allegedly used the popular social media site Yik Yak to post a threat. Police say the post warned there would be a shooting at the high school Tuesday, and then the building would be blown up.

Suffolk police were able to identify the ninth-grader and charged him with making a terroristic threat.

The school said in a statement to News 12, "The district has stayed in constant contact with law enforcement officials throughout the investigation and, as a precaution, police will continue to have a presence at all three schools today."

Yik Yak promotes itself as a service that allows users to share thoughts anonymously. Suffolk County Legislator Sarah Anker wrote a letter to the company demanding that it do more to monitor and remove threatening or violent posts.

A second reported threat of an attack at West Islip High School Monday was also investigated by police. It was determined to be unfounded.