San Diego-based Seaman Benjamin D. Rast died April 6 in Helmand province according to the U.S. Department of Defense.
Rast, 23, of Michigan, a medic, was on patrol northeast of Patrol Base Alcatraz in Afghanistan when he was killed Wednesday.
His high school girlfriend told a Michigan television reporter that Rast studied law enforcement and always dreamed of becoming a sailor.
Rast's father told WNDU he fears his son may have been killed by friendly fire.
The incident is under investigation, according to the DOD news release.
Rast was stationed at Naval Medical Center, Expeditionary Medical Force Detachment. The staff established an electronic memory book as a way to share memories. It will be compited and provided as a tribute to Rast's family, according to a medical center spokesperson.
Rast enlisted in the U.S. Navy in April 2009. His awards included National Defense Service Medal, Pistol Markmanship Medal and Global War on Terrorism Service Medal.