An 18-year-old has turned himself in after police say he made threats to commit harm to a Virginia School.

Ishmael Harrison turned himself in Monday after warrants were obtained for one count of threats to commit serious bodily harm to persons on school property and another for possession of child pornography.

Police say Harrison was a student at Fairfax High School. The threats were first seen on Twitter and then were reported to police.

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On Sunday, police released new information that Harrison's home was searched on March 2, leading to the discovery of rifle ammunition.

Police said they were providing enhanced security to Fairfax City schools.

Police say they first went to the school resource officer, then went to administrators. They even got parents to call the city police chief on his personal cell phone.

Police say the threats started two weeks ago. It’s not exactly clear if he would have carried out the threats on the school, but police say officers found that Harrison had rifle ammunition.