Capt. John W. Maloney, 36, who was born in California but grew up in Chicopee, and Lance Cpl. Erik R. Heldt, 26, of Hermann, Mo., were conducting combat operations near Ar Ramadi, Iraq, on Thursday when their vehicle hit an "improvised explosive device," killing them, according to a statement released by the Department of Defense. Both men were assigned to the 1st Battalion, 5th Marine Regiment, 1st Marine Division, I Marine Expeditionary Force, based at Camp Pendleton, Calif. During Operation Iraqi Freedom, their unit was attached to the 2nd Marine Division, II Marine Expeditionary Force.