UPDATE: 17-year-old Austin Wyatt Rollins is dead after he brought a handgun to school and engaged an armed school resource officer.

Deputy Blaine Gaskill, the school resource officer, was not injured in the shooting.

According to Fox News, St. Mary's County Sheriff Tim Cameron said there were indications Rollins and the 16-year-old female victim had a prior relationship, which police are investigating as a possible motive for the incident. She is currently in ICU in critical condition.

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UPDATE: Local reports say the gunman, who was shot by the school resource officer, has died from his injuries. The officer shot him after the gunman went to the Maryland campus and shot two fellow students. One of the students, a female, was critically wounded, while a 14-year-old male student is now in stable condition, according to FOX News.

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GREAT MILLS, Md. (AP) — The Latest on the shooting at a Maryland high school (all times local):

10:45 a.m.

The principal at the Maryland high school where there was a shooting Tuesday morning told parents last month that the school had investigated threats of a possible shooting and found they were "not substantiated."

Great Mills High School Principal Jake Heibel told parents that school officials interviewed two students in February who were overheard mentioning a school shooting and found that they posed no threat. His letter was posted on the local news site The Bay Net.

But Heibel said the school still increased its security after social media posts about a possible school shooting "circulated quite extensively."

St. Mary's County Sheriff's spokeswoman Cpl. Julie Yingling says three people, including the shooter, were injured in Tuesday's shooting.

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10:15 a.m.

A sheriff's spokeswoman says three people have been injured in a shooting at a high school in southern Maryland, including the shooter.

St. Mary's County Sheriff's spokeswoman Cpl. Julie Yingling says there have been no fatalities in the Tuesday morning shooting at Great Mills High School.

Yingling says the two victims were shot, but she doesn't know how the shooter was injured. She also didn't have the identities of the any of the three injured.

She says all three had been transported to hospitals.

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10 a.m.

FBI agents are on the scene of a shooting at a high school in southern Maryland.

FBI spokesman David Fitz says the agents are there to assist the local sheriff's office and he had no immediate information about injuries or fatalities at Great Mills High School.

Agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives have also been sent to the school.

The county sheriff said deputies are on the scene and that parents or guardians should stay away, going instead to Leonardtown High School to reunite with Great Mills students there.

Local and social media first reported a shooting on the campus of Great Mills High School in Great Mills, Maryland. FOX News has confirmed the shots fired. One student reported that one person was dead. Law enforcement sources have not confirmed those details at this point.

The school is on lockdown and is located south of Washington, D.C. and parents have been told not to report to the high school. The St. Mary's County Sheriff says the incident is "contained".

The FBI is on the scene as well as ATF officials from the Baltimore field office. The shooting comes just about a month after the mass shooting at Parkland High School.