A months-long investigation into a fatal fentanyl overdose of a Michigan man has led to charges against two Plymouth residents.

Indiana State Police say 35-year-old Ernest Westerhoff and 32-year-old Alyssa Kring were each charged Thursday with Dealing in a Controlled Substance Resulting in Death.

The investigation began in April after the victim was found dead in his vehicle in Michigan.

An autopsy determined fentanyl was among the drugs that caused his death. Authorities say the investigation tied the fatal dose to Westerhoff and Kring.

Both appeared in court with bonds set at $100,000 cash each.