A teenager charged with making a terroristic threat against Sewanhaka High School had no comment after his arraignment in Hempstead court Wednesday.

Prosecutors say Joseph Khanat, a 17-year-old from Elmont, posted two photos to Snapchat that were seen by at least 50 students at the Floral Park school. 

Khanat was released without having to post bail. He left the courtroom with a jacket pulled over his head to hide his face. 

Neither Khanat nor his parents, who also attended the court appearance, said anything to reporters. 

According to prosecutors, he had much more to say on social media. In one photo, he allegedly held a black Uzi, captioned with threats to shoot his assistant principal if he was called down to the office. The other photo showed the high school in flames.

Khanat is the third Nassau teen charged with a felony for allegedly making school threats in roughly the last three weeks.

As News 12 Long Island has reported, two days after a massacre in a Florida high school, 18-year-old Andrew Davies of Valley Stream North High School allegedly made a verbal threat that someone recorded and put on social media. And last Friday, 17-year-old Youssef Mohammed was arrested for allegedly making a threat against Farmingdale High School. 

"Parents have to have a serious conversation with their kids," said Nassau Detective Lt. Richard Lebrun. "If they're over 16, it's a criminal charge of making a terroristic threat -- a D felony."

Suffolk police have responded to 109 school threats so far this year. Nassau police have responded to more than 40.

The crime is punishable by a seven-year sentence.