A 71-year-old Williamsburg businessman faces 20 years in prison on drug charges following an undercover investigation of his now-shuttered medical marijuana dispensaries.

Michael John Hedden faces seven counts, including conducting a criminal enterprise, delivery and manufacture of marijuana, and maintaining a drug house following an investigation by the Traverse Narcotics Team.

An undercover police officer visited three stores owned by Hedden last September and October and purchased marijuana using a state-issued medical marijuana card; two former employees cooperated with investigators and will testify against Hedden, according to the charges.

Hedden’s owned the Boutique and Compassion Center on State Street and the 809 Provisioning Center on Garfield Avenue in Traverse City and Great Lakes Healing Hands on M-72 in Acme. He faces a preliminary hearing July 18.

TNT’s last undercover purchase in the case was on Oct. 2; on Oct. 4, law enforcement officials in Grand Traverse County announced that eight medical marijuana dispensaries had been raided and ordered closed across the county.

Prosecuting Attorney Bob Cooney says he's only received a criminal complaint for Hedden, not the other owners, "probably because Heddon was in charge of a sophisticated operation with three store fronts and the others were more mom and pop."