The suspects, from the city's Montebello area, are expected to face charges including murder and attempted murder, as well as drug and robbery conspiracy, the Los Angeles Times reported, citing people familiar with the investigation.
Local and federal authorities said the operation -- named "Sudden Impact" after the 1983 Clint Eastwood movie -- looked into drug and turf rivalries.
One of the most prominent suspects, Jimmy Valenzuela, 30, was arrested last June in two apparently gang-related killings.
Chipotle plans first price increase in 3 years
Justin Bieber crashes Drake Bell's album release party