Prosecutors said both men paid tens of thousands of dollars to Natividad "Nate" Cervantes in exchange for contracts at Camp Pendleton.
The shooting occurred at 9:45 p.m. Friday, in the 1600 block of Cathy Street.
The suspect was described as a clean-shaven, light-skin man in his 20s or 30s, 5 feet 8 to 5 feet 10, wearing a black T-shirt, blue pants and black baseball cap.
Joseph Robert Gentile, 59, was taken into custody for allegedly killing Guillermo "William" Saavedra.
WRTC2014 gathers competitors, referees, and visitors from around the world to connect and celebrate amateur "ham" radio.
Race up your tennis shoes, the challenge starts July 14.
Kevin McCalla was found lying on a sidewalk in an apartment complex at about 8:45 p.m. Wednesday.
In both robberies, a suspect allegedly fired his gun into the ceiling.
Bill Earley will be its next chief executive at the San Diego and Imperial Counties Chapter.