Authorities suspect the painkiller fentanyl, mixed with either heroin or cocaine, is to blame for a spike in drug overdose deaths involving 50 people in Wayne County during the past two weeks, including two on Wednesday. Mark Greenwald, Wayne State University psychiatry professor, says there are still a lot of questions, but all evidence points to it being a mix that came onto the street from illegal networks. According to experts, the drug is being clandestinely manufactured, but not in the Detroit or Wayne County area, and that it was brought here and sold here.