Police say a teen was charged after a threatening Snapchat post that appeared to show an assault rifle drew a police response to Southampton High School's homecoming after-party.

Southampton Village police say they were alerted to the threat shortly after 9:30 p.m. Saturday, after a student notified security personnel at the high school. About 110 students were attending the after-party at the school when police responded and the building was placed in lockout mode.

Police say the Snapchat post showed three males in a vehicle brandishing what appeared to be an AR-15 and stated, "Pull up to after homecoming SH."

More than 20 officers, including Southampton Town officers and state troopers, responded with K-9 units to secure a perimeter around the school.

Students were released to their families without issue, and police say the building and street were reopened shortly before 11 p.m.

Police say 19-year-old Kevin Chavez, of Bridgehampton, was arrested in connection to the incident.  Police say they recovered a replica AR-15 from a home that was actually a Sig Sauer air gun. They say it was the weapon that was brandished on Snapchat.

Chavez was charged with third-degree falsely reporting an incident, a misdemeanor, and was released on a desk appearance ticket. Police say he was taken to Stony Brook University Hospital for a psychological evaluation.

Investigators are urging anyone with additional information on the incident to call the Southampton Village Police Department at 631-283-0056.