The Douglas County Sheriff’s Office put Rock Canyon High School in Highlands Ranch on a brief lockdown Thursday after a student was seen with a pellet-type gun on school grounds. 

Authorities received a report of a man possibly armed with a rifle in the school’s parking lot around 9:30 a.m. The caller told dispatchers they believed they “heard 3 to 4 popping sounds,” according to the Sheriff’s Office.

The school resource officer and other deputies responded to the parking lot while the school was put on lockdown.

Within minutes, over 25 law enforcement officers were at the school to investigate the incident. 

Deputies found a 17-year-old student outside of the school with a pellet-type gun. 

Authorities notified the student’s parents, who were cooperating with the investigation, according to the Sheriff’s Office.

Deputies lifted the lockdown just before 10:30 a.m.