BANGOR – The last man facing federal charges in a Waldo County drug ring was sentenced Wednesday to two years in prison and five years of supervised release.

William Stevens, 64, pleaded guilty in July in U.S. District Court in Bangor to one count of possession with intent to distribute cocaine and heroin and aiding and abetting the commission of those crimes.

The Frankfort resident admitted that he drove to Massachusetts and picked up drugs with his granddaughter’s boyfriend, Russell Belden, but was not aware when he left Maine he was acting as a mule in a large drug ring, according to Assistant U.S. Attorney Daniel Perry.

The Waldo County operation was dubbed the “Red Devil” heroin ring by some law enforcement officials.

Stevens faced a mandatory minimum sentence of five years because of his criminal history that includes a 1996 conviction for operating under the influence of intoxicants and a 1992 conviction for criminal trespass.

His attorney, Spencer Ervin of Bass Harbor, successfully argued that the 1992 charge should not be counted because it was not clear that Stevens had waived his right to an attorney.

The form used by the 5th District Court in Belfast in 1992 included a question about whether a defendant had waived, retained or been appointed an attorney.

But the form used in Stevens’ case did not indicate that he had hired or retained an attorney. It also did not indicate that he had waived his right to an attorney. Citing a recent 1st Circuit Court of Appeals opinion from a Maine case, Ervin successfully argued that it could not be shown that Stevens had waived his right to an attorney.

“You are lucky to have a lawyer who has been persistent and innovative in his pursuit of [a sentence reduction],” U.S. District Court Judge John Woodcock told Stevens. “You were foolish to an extreme to engage in this conduct. … You were nothing but a mule. A mule is known to be a stupid animal and you did something unbelievably dumb.”

Six other people were sentenced previously in federal court after pleading guilty to drug charges for their parts in the scheme.

Timothy Paggi, 31, of Lowell, Mass., was sentenced in September in U.S. District Court in Portland to 35 months in prison and four years of supervised release for conspiracy to possess with intent to distribute cocaine and heroin.

Tristan Grasso, 27, of Northport admitted that he conspired with Robert Orchard, 55, of Northport and Belden, 39, of Brooks to bring raw heroin to Maine from New York and Massachusetts, according to court documents.

In March, Orchard was sentenced to 101/2 years in prison and Belden to 13 years as leaders of the “Red Devil” heroin ring.

Two other members of the group were sentenced in August. Peter McLaughlin, 40, of Lincolnville was sentenced to 35 months in prison and Demain Michael Sullivan, 33, of Liberty was sentenced to 32 months in prison.