These street gangs are involved in crimes such as assault, auto theft, bank robbery, carjacking, drive-by shooting, homicide, assault on law enforcement officials, weapons distribution, and home invasion in furtherance of their gang objectives and to protect their gang turf. Arrests for heroin-related offenses numbered 7,214 in San Francisco County in 1998, a 10 percent increase over 1997 and the highest number in 6 years. However, few agencies report violence associated with heroin use, in contrast to methamphetamine use. There were 17 percent fewer burglaries in the first 10 months of 1999 than in the same period of 1998. According to the Sacramento County Sheriff's Office, responding to the NDIC National Gang Survey, members affiliated with Nuestra Familia and the Northern Structure sell heroin, marijuana, and methamphetamine locally and outside California.
Some members specialize in armed robberies.
Police in Seaside apprehended other Northern Structure members who were using portable radios and police scanners and apparently planning a drive-by shooting in retaliation for an assault on one of their leaders. Officers believe their plan was to use one car to lure officers from their normal patrol area, a second car to notify other members of the location of patrol units, and a third car to commit the drive-by shooting. In April 1997, California authorities reported 597 members and 144 associates of Northern Structure incarcerated in the California Department of Corrections. In West Oakland, the Black Guerrilla Family, a prison-based gang, distributes heroin and commits violent crimes such as contract murders and robberies. The Black Guerrilla Family evolved from the 1970s radical prison movement in California, and is considered extremely violent.