A Department of Defense educator and U.S. Army captain have been snared as part of a statewide child-pornography investigation, authorities said.Liberty County Sheriff Steve Sikes said Dirk Allen Burchard, 34, a third-grade teacher at Murray Elementary on Fort Stewart, was arrested Thursday and charged with several counts of child pornography.Sikes said the investigation into Burchard began when members of the Georgia Internet Crimes Against Children Task Force received a tip from the Sherburne County Sheriff’s Office in Elk River, Minnesota. That same task force announced the arrest of 18 other individuals — including Army Capt. Samuel Oh, 30, who is with the 3rd Infantry Division and is stationed at Fort Stewart — in a news release issued Thursday by the Georgia Bureau of Investigation. Sikes said his deputies, along with members of the state task force and the Army’s Criminal Investigation Command, arrested Burchard.Fort Stewart spokesman Kevin Larson confirmed the arrest of the teacher along with confirming that Oh is stationed at the post and is with the 3rd ID.Task Force Officer Chuck Woodall, who was present when Burchard was arrested, said the teacher was taken into custody without incident at Murray Elementary.