A shooting at aMaryland high school has left one person dead ​and two injured, all before a school resource officer engaged the gunman and ended the threat. 

St. Mary’s County Sheriff Tim Cameron told CNN a male student is in stable condition and a female student in critical condition after the incident. The shooter was later pronounced dead. 

“The school resource officer fired a round at the shooter, and the shooter fired a round as well, but the officer was not injured,” CNN reports.

In an email to ​Security Management magazine, Mo Canady, executive director of the National Association of School Resource Officers, says the organization is "very pleased with the actions of the SRO."​

The gunman has been identified as Austin Wyatt Rollins, 17; the sheriff's office says it is unclear whether he died of a self-inflicted gunshot wound or from the SRO's bullet. The investigation is ongoing.​

Original reports said that three people had been injured in the shooting at Great Mills High School; the campus was on lockdown for a brief time and students were evacuated to a nearby school that served as a reunification center. 

FBI’s Baltimore field officer posted on Twitter that its agents are on the scene of the incident, as well as agents from the U.S. Federal Bureau of Alcohol, Tobacco, and Firearms. The FBI is requesting anyone with information related to the shooting contact its office.

As CNN reports, this shooting is the 17th at a school in the United States this year.The school had drilled for this type of situation a couple times in the past​, according to a student who called the media outlet from inside the school during the lockdown.