Soon after, Omar Roebuck left for Helmand province in Afghanistan, on the Pakistani border. It was his first tour of duty. He was assigned to the 2nd Combat Engineer Battalion, 2nd Marine Division, 2nd Marine Expeditionary Force at Camp Lejeune, N.C.
Roebuck's father, an Army veteran, said his son had joined the Marine Corps after carefully researching the various branches of the U.S. military.
John Roebuck said his son had hoped that military experience would help prepare him for a career with the California Highway Patrol. He had dreamed of eventually becoming a CHP helicopter pilot.
But those hopes ended Dec. 22 when Omar Roebuck, a mechanic, was crushed to death by a tank he was working on with his sergeant, his sister said. He was 23.
"It's really hard," John Roebuck said of his son's death. "We were really close; we talked about everything, and, early on, he told me I was his best friend. . . . Sometimes I just can't stop thinking about it."
The elder Roebuck said he has made several visits to his son's grave site at Riverside National Cemetery. And Eboni Roebuck said she draws a measure of comfort in knowing that her brother didn't suffer. "At least he went quick," she said.
Born in Los Angeles, the youngest of six, Omar Roebuck and his sister went to live with their father in Perris when Omar was 12. The family later moved to Moreno Valley, where the boy became close to the couple next door, Pat and Connie Tatum. He called her "Mom" and relished her homemade enchiladas, John Roebuck said.
"They were such good kids -- neither one of them ever gave me any trouble," he said of Eboni and Omar.
Omar attended Perris High School, then went on to graduate from March Mountain High, an alternative school, after the family moved.
He worked at several jobs after high school, including at a distribution warehouse for a sporting goods chain, at a supermarket and in security before deciding to go into the military.
Smart and friendly, he enjoyed working out and loved motorcycles of all types -- he started riding at age 4, his sister and father said.
He was an amateur boxer and had won "a ton of trophies," his father said. He also enjoyed going to movies and listening to music, especially rhythm and blues classics.
His sister said she jokingly called him "Fat Boy" because he was in such good physical condition.
John Roebuck said he is especially proud that his son excelled in the military. Omar Roebuck was a leader of his boot camp class, finishing second in the class and earning his family reserved seating at the graduation ceremonies, his father said.
In a letter to John Roebuck, Marine Corps Brig. Gen. L.D. Nicholson praised the young man as the type of Marine everyone wanted, citing his positive attitude and personal charisma.
Father and son spoke by phone and e-mail "whenever we could" during Omar's deployment in Afghanistan, John Roebuck said.
Omar told his father that he was working on a new type of tank, the first of its kind. "So he was a part of history," his father said.
Eboni Roebuck, who now lives in Barstow, said she believes that her brother, who was single, will be remembered by his many friends for his radiant smile and hearty laugh.
"Even though he was young himself, he had a wisdom beyond his years -- an old soul in a young person's body," she said. "To describe him in one word, 'amazing.' "