Detroit — A controversial auto shop owner moved Tuesday to dismiss his federal lawsuit alleging the city and Mayor Mike Duggan retaliated against him over a land dispute.

The action by businessman Robert Carmack comes less than one week after U.S. District Judge Matthew Leitman said he had "very serious concerns" over how the lawsuit was being prosecuted.

The move drew a swift response from the city. In a Wednesday filing, the city called Carmack's request for dismissal an "attempt to game the system" and called for the judge to delay action on Carmack's request.

Carmack is the central figure in the bribery indictment against Detroit City Councilman Gabe Leland and says he wore a secret recording device during conversations with the Detroit city councilman — portions of which are included in the indictment. Leland is accused of agreeing to accept $15,000 and free car repairs from Carmack.

Carmack also is engaged in a high-profile spat with Duggan. Last month, Carmack broadcast video shot by a private investigator showing the mayor visiting a condominium in Novi and separately showed a woman arriving there on other occasions.

Carmack sued the city, the Detroit Building Authority, Duggan, Leland and others in March. In a court filing late Tuesday, Carmack notified the court he intended to drop the lawsuit.

The city explained its position in its filing Wednesday, saying Leitman last week ordered the parties to discuss a settlement and to advise his clerk on the status of the discussions "before the court issues a decision on defendants' motion."

"... What I would like to do is to give you and Mr. Carmack a week or so to - - you can talk to him about the hearing and my questions and concerns," Leitman said, according to the filing. "... Then communicate back ...whether you wish to persist with the action or if the defendants are willing not to pursue any sanctions, if that would be an appropriate resolution."

Carmack, the city's filing said, "has no intention of resolving the dispute with defendants, which he brought before this court many months ago."

His spokesman, Michael Bsharah, said he was "confident that Mr. Carmack's ongoing actions and concerns will be judiciously worked with on the matter."

In a statement Wednesday, Carmack's attorney Andrew Paterson said his client is considering pursuing a new lawsuit in state court against Leland.

"The voluntary dismissal of Mr. Carmack's claims against the city of Detroit, Mike Duggan, and the Detroit Building Authority were dismissed without prejudice, which means Mr. Carmack can refile these same claims, in addition to new claims, in either state or federal court, if he so desires," Paterson said.

"Based upon Mayor Duggan's recent threats, Mr. Carmack is contemplating whether to file additional federal claims against Mayor Duggan and others for retaliating against him for exercising his First Amendment rights.

"Contrary to the city's flawed and erroneous statement, Mr. Carmack has properly pled and alleged meritorious claims against the Mayor, the City of Detroit, the Building Authority and Councilman Gabe Leland," Paterson said. "In fact, the facts pled and alleged in Carmack's meritorious federal case were instrumental and ultimately led to the indictment of Councilman Leland."

Leitman was already considering dismissing portions of the lawsuit.

On Nov. 28, the judge held a hearing and expressed concern that Carmack's undercover surveillance of the mayor, and threats to release new footage, were an attempt to influence the lawsuit.

"I would have grave concerns if I learned that a litigant before me was directing, toward an opposing litigant before me, a direct or implied threat to release information about that litigant in order to take a certain position in the litigation," the judge told Paterson. "Would you communicate that to Mr. Carmack so he’s not confused about my view of the world?"

Leitman also told Paterson to consider whether he and his client may want to drop the case altogether, noting while he hasn't made any decision yet, the defense arguments have "very substantial merit" and he has "very serious concerns about how this case is being prosecuted."

In the lawsuit, Carmack alleged the city and mayor retaliated against him for exercising his free speech rights during a March 2015 City Council meeting about a nearly decade-old development deal for property along the city's riverfront.

He also contends he was targeted in response to a subsequent television news report tied to the city's effort to tear down a Michigan Avenue property he maintains he owned. He's seeking damages of more than $1 million.

“Mr. Carmack has been involved in several ‘land disputes’ with the City of Detroit, but he has never won any," Lawrence Garcia, Detroit's corporation counsel, said in a statement. "The paperwork he filed last night proves that his case in federal court has no merit. However, it does not address concerns about Carmack’s misuse of the legal system.

“My office will continue to press for full and final resolution of these baseless claims and an end to Mr. Carmack’s abuse of the process.”

James Noseda, an attorney for the city, said during the hearing last week that he, Carmack and others met about a month ago to discuss settling multiple pending cases, including a separate suit filed by the city that alleges Carmack fraudulently sold a city-owned property for $1 million.

Carmack, he said, made clear he'd "rain hellfire on the mayor if it didn't go away," Noseda told the judge.

Noseda called the federal complaint "frivolous" and told the judge it has "absolutely no allegation of individual conduct by the mayor."

Duggan last week asked the Michigan State Police to investigate whether Carmack's recent actions amount to extortion.

Carmack has denied the claim that he's attempted to extort the mayor.

rsnell@detroitnews.com

(313) 222-2486

Twitter: @robertsnellnews

Staff Writer Christine Ferretti contributed.