INDIANAPOLIS – Four soldiers with an Indiana-based National Guard unit were killed in Afghanistan and a fifth was injured when their vehicle struck a roadside bomb as they were working to clear a supply route of the improvised bombs, guard officials said Saturday.

Indiana Adjutant General Martin Umbarger said the four members of the Valparaiso-based 713th Engineer Company died Thursday morning in southern Afghanistan. He said all of the men were combat engineers who specialized in clearing major supply routes.

“Their mission is to keep the major supply routes clear of all obstacles for the convoys. And what that means is they’re the first ones to go out to make sure the route can be used, so it’s a very important mission — but it’s also extremely dangerous,” Umbarger told The Associated Press.

The four men killed were identified as Staff Sgt. Jonathan M. Metzger, 32, of Indianapolis; Spc. Brian J. Leonhardt, 21, of Merrillville, Ind.; Spc. Robert J. Tauteris Jr., 44, of Hamlet, Ind.; and Spc. Christopher A. Patterson, 20, of Aurora, Ill.

A fifth soldier injured in the blast, Pvt. Douglas Rachowicz, 29, of Hammond, Ind., was being airlifted to a U.S. military hospital in Germany, Umbarger said.

Tauteris’ uncle, Ed Tauteris of North Judson, Ind., said his nephew reenlisted in the National Guard after his 21-year-old son, Robert III, joined up and was sent to Afghanistan. He said his nephew had hoped he might be able to keep his son safe during his deployment.

He said Robert Tauteris III accompanied his father’s body back to the U.S.