BROWNSTOWN TOWNSHIP, Mich. – Businessman Robert Carmack -- best known for hiring a private investigator to follow Detroit Mayor Mike Duggan -- has been charged with a drunken driving offense that could send him to prison, officials said.

Brownstown Township police arrested Carmack on Oct. 27, according to authorities. He was arraigned Friday.

Robert Carmack (WDIV)

Carmack’s case would normally fall to the Wayne County Prosecutor’s Office, but due to his controversial recent past -- which includes calling Duggan a criminal and wanting the mayor locked up and his arrest for allegedly selling a city property he didn’t own for $1 million -- Kym Worthy recused herself in the case.

In November, the case was handed off to the Michigan Attorney General’s Office.

Authorities said Carmack went to a bar the night of the incident and an officer saw he was obviously intoxicated when he left.

Police said the officer stopped Carmack and told him to go back inside and get a ride home.

About 10 minutes later, Carmack came back out and put the keys in the ignition of his red 2019 Corvette, according to authorities. That’s when the officer arrested Carmack, officials said.

Carmack is charged with operating under the influence -- third offense, which means he’s had prior incidents. His driving arrest shows four prior drunken driving arrests -- all in the 1980s and early 1990s.

Records show he’s also had his driver’s license suspended and renewed a number of times in recent years.

Local 4 reached out to Carmack for comment, but he didn’t return the call. His attorney had no comment.

A probable cause conference is scheduled for Jan. 3, and a preliminary examination is scheduled for Jan. 7.

Carmack entered a not guilty plea and was released on $5,000 bond, 10% surety, officials said. He was ordered not to consume alcohol while the case is ongoing.

If convicted, Carmack could face up to five years in prison and/or a $5,000 fine.