GREAT MILLS, Md. -- Shots were fired inside a Maryland school Tuesday and the school was put on lockdown. But this time, it appears a school resource officer took action and stopped a potentially bigger problem.

"I didn't really believe that something like this would happen to a school near me," said student Makayla Bonds. "It's really scary."

Shortly before the opening bell, the call went out for "shots fired" at Great Mills High School in Maryland. Police say 17-year-old Austin Wyatt Rollings opened fire in a hallway and shot a 16-year-old girl, Jaelynn Willey.

"There is an indication that a prior relationship existed between the shooter and the female victim," said Sheriff Tim Cameron.

Deputy First Class Blaine Gaskill, school resource officer at Great Mills High School in Maryland St. Mary's County Sheriff's Office

Blaine Gaskill, the school resource officer and a former SWAT team member, responded within a minute, firing one round. Investigators say Rollings fired his semi-automatic handgun at the same time.

He was later pronounced dead but its not clear whether the officer shot him or if he shot himself. A 14-year-old boy was also wounded in the incident.

"No question that his actions, his quick and immediate actions, potentially saved a great number of lives," Cameron said of Gaskill.

We spoke to one mother who rushed to reunite with her daughter. When we asked her what that was like, she said, "Panic."

The school district's superintendent, James Smith, said what happened is not so unusual any more.

"If you don't think this [can] happen at your school, you are sadly mistaken," said Smith.

The 16-year-old girl is fighting for her life, and the 14 year old was shot in the leg and is expected to survive. Investigators say there is video of the shooting, which should help them figure out exactly what happened.