The Tennessee Bureau of Investigation’s Drug Investigation Division is urging public caution, especially among recreational drug users, following recent evidence submissions to two TBI crime laboratories. Several samples of cocaine, submitted by law enforcement agencies in Middle and East Tennessee in recent months, also tested positive for fentanyl, a powerful, narcotic painkiller, or one of its dangerous analogs. The recent submissions mark the first time samples of cocaine have tested positive in a TBI laboratory for fentanyl.