The fourth meeting of the 31st session of the Martin Police Department Citizens Police Academy learned about various forms of illegal drugs and the methods that law enforcement uses to counter the illegal drug trade.  Inv. Scott Diehl taught a segment on street drugs, explaining the different types of drugs and their effects.  Capt. Tommy Erwin instructed two segments, one on undercover drug operations and another on drug interdiction techniques.  Sgt. Marty McClure finished the night with a segment on just explosives K9 and how they operate together to locate explosives and firearms.