Each state's department of justice has a section that prosecutes drug-related crimes. Most state justice departments have a subordinate drug enforcement bureau that investigates narcotics cases and operates its own specialized operations. These state bureaus usually include units that can locate and dismantle clandestine drug labs, train local law enforcement agencies and provide other services.
The narcotics unit of the California State Department of Justice is typical. Established in 1927, it is called the Bureau of Narcotics Enforcement and operates the state's Campaign Against Marijuana Planting, a clandestine laboratory enforcement program, a drug prevention education unit, a financial investigations program aimed at money laundering and a host of other activities.
State narcotics divisions like the one in California usually work closely with federal and local law enforcement agencies in “task force” operations aimed at major traffickers.
Your state attorney general probably has a website that will have links to its drug enforcement unit, including the press office for the agency.
The National Association of Attorneys General, http://www.naag.org/, has a comprehensive listing of all state attorneys general with links to each AG's website.