Daniel Katusich was arrested Wednesday by a gang task force outside a Vista apartment.
Sheriff's Lt. Derek Clark says the 23-year-old Katusich was wanted in Massachusetts after a grand jury indicted him for a firearms violation. He did not have details.
Sheriff's Sgt. Scott Miedecke says another man, 23-year-old Kenneth Ludwig, was arrested on suspicion of harboring a fugitive.
The sergeant says two other men, one of them a cousin of Katusich, were later arrested after drugs and a stolen gun were found in the apartment.
All four men remained jailed Thursday.