A coordinated construction apparatus exists for fortifying rock houses. Coordinated transport systems also exist. Some suppliers, transporters, and dealers use commercial radio beeper systems with coded messages. Some dealers own several rock houses. Currently, the problem exists only in the black community. The level of rock sales makes it clear that an easily available cheap supply can dramatically increase demand. Serious violence and gang involvement are now associated with sales of rock cocaine. The intrusion of gangs into drug sales is of particular concern, because narcotics officers lack sophisticated understanding about how to recognize gangs and how they are organized. In Los Angeles, these problems have required an unprecedented level of coordination among police agencies. 5 references