Eight people were arrested Monday in a bust of a major marijuana growing operation that included four grow houses in Daly City and South San Francisco, the San Mateo County Sheriff’s Office said Tuesday.

Police seized 1,400 marijuana plants, 55 pounds of harvested marijuana, six guns and more than $47,000 in suspected drug profits, Sheriff’s Department spokesman Lt. Ray Lunny said. The marijuana seized has an estimated street value of more than $450,000.

The bust is a result of nine months of undercover investigation. According to Lunny, the suspects were members of a “close-knit” Asian drug trafficking organization. They are not associated with any known medical marijuana collectives.

Police obtained nine search warrants for the case. During the search, police found four of the homes were indoor grow sites, the remaining were locations were residents of suspects or co-conspirators.

Included in the arrests were San Francisco residents Steven Pham, 25, Tue Pham, 37, Marvin Pham, 27, and Brian Wong, 31. All are charged with cultivation of marijuana, possession of marijuana and criminal conspiracy. Each person is held on $1 million bail.

Four Daly City residents were arrested and face similar charges including Nam Nguyen, 29, Danny Nguyen, 22, Bong Nguyen, 51, and Donna Quach, 28. All four are also held on $1 million bail.

akoskey@sfexaminer.com