3 injured in Maryland high school shooting

Teachers and school employees depart Great Mills High School, the scene of a shooting, March 20, 2018 in Great Mills, Md. A teenager wounded a girl and a boy inside his Maryland high school Tuesday before an armed school resource officer was able to intervene, and each of them fired one more round as the shooter was fatally wounded, a sheriff said. St. Mary's County Sheriff Tim Cameron said the student with the handgun was declared dead at a hospital, and the other two students were in critical condition. He said the officer was not harmed.

School buses are lined up in front of Great Mills High School after a shooting on March 20, 2018 in Great Mills, Md.

A police officer stands in front of Great Mills High School after a shooting on March 20, 2018 in Great Mills, Md.

A gate is locked in front of Great Mills High School after a shooting on March 20, 2018 in Great Mills, Md.

Police vehicles pull out of Great Mills High School after a shooting on March 20, 2018 in Great Mills, Md.

A man looks out of a school bus at Great Mills High School in Great Mills, Md. after a shooting at the school, March 20, 2018.

A policeman gives a thumbs-up after moving students into a different area of Great Mills High School, the scene of a shooting, March 20, 2018 in Great Mills, Md. .