SOUTH GATE, Calif. (KABC) -- When Joseph Maciel graduated from South Gate High School, he had Army ambitions and the blessings of his family.
Maciel's father Jose Leal spoke to his 20-year-old son last Friday, just hours before the corporal was killed while on deployment in Afghanistan.
"He was always smiling," Leal said. "He never complained. He said 'I am going, I got to serve my country.' Do what you got do. I was very proud."
Obeying military protocol, Maciel could never share mission details with his family. They knew only that he was in Afghanistan, where the U.S. had been withdrawing combat troops.
However, American military advisors remained in the Middle Eastern county to support the Afghan National Army.
According to the Department of Defense, newly designed Security Force Assistance Brigades were formed and had been working close to the front lines.
Cpl. Maciel's unit, the 1st Battalion, 28th Infantry Regiment out of Fort Benning Ga., was tasked to protect the advisors.
An Afghan insider posing as a U.S. partner killed Maciel over the weekend.
"They turned on our armed forces," Leal said. "I am very shocked because we try to help that country."
The South Gate High School graduate posthumously received a Bronze Star and Purple Heart.
Maciel had served two years with the Army infantry prior to his death and was planning to re-enlist.
"I never regret that my son joined the Armed Forces," Leal said. "I am proud of him. He loved what he was doing."