Military officials say Army Staff Sergeant Oscar Vargas-Medina was killed over the weekend by Shiite militiamen who attacked his military supply convoy.
His mother, Francia Lopez, says she last heard from her son on Thursday. He called to tell her that his unit was being sent to Fallujah on a "dangerous mission" and to thank her for a care package she'd sent.
Lopez says her son loved the Army and had been deployed to Kosovo, Korea and Kuwait during 12 years in the service.
Vargas-Medina was assigned to the 84th Engineer Battalion, 25th Infantry Division (Light) based at Schofield Barracks in Honolulu.