One student was arrested and one was disciplined Monday after threats were made against schools in Prince George’s County in separate incidents, police said.

A student at Parkdale High School in Riverdale was arrested after he set up a Twitter account with a clown theme while in class and threatened to harm people at the school, Prince George’s County police said in a statement.

The student, who was not identified by police because he is a juvenile, was charged with making a threat of mass violence, the statement said.

The statement also said police identified a student at Bladensburg High School who made a bomb threat against the school over social media that did not appear to be credible. The student, who was not named by police because he is also a juvenile, was disciplined by school officials and criminal charges were not filed pending additional investigation, according to the statement.

“While perpetrators may believe certain apps provide anonymity, these investigations show otherwise,” Prince George’s County Police Chief Hank Stawinski said in a statement.

Police asked anyone with information about these incidents to contact them at 1-866-411-TIPS or submit a tip to www.pgcrimesolvers.com.

They also asked anyone who sees threats of violence on social media to call authorities instead of forwarding such posts to help police more quickly trace where the threats came from.