Prosecutors moved Monday to drop pay-to-play charges against former Utah Attorney General Mark Shurtleff, a surprise retreat more than two years after state investigators arrested the former top lawman and his successor, citing a pattern of favors and gifts traded with a cast of questionable Utah businessmen.

Davis County Attorney Troy Rawlings said in court documents that a recent U.S. Supreme Court decision overturning the bribery conviction of former Virginia Gov. Bob McDonnell narrowed what could be charged in influence-peddling cases.

Rawlings, a Republican, also said federal investigators stopped cooperating with the prosecution of Shurtleff and did not hand over evidence from past federal investigations. Rawlings said he had to drop the case because it would violate a constitutional right to a speedy trial.

Shurtleff's defense attorney Richard Van Wagoner said in a statement that his client is gratified and that prosecutors in court documents had acknowledged arguments made by Shurtleff that the case should be dismissed.

Van Wagoner said his client would not comment further until a judge ruled on the matter. It's unclear when that might be.

Shurtleff, a Republican who spent a dozen years as Utah's attorney general, had pleaded not guilty to seven counts of obstructing justice and accepting improper gifts such as beach vacations from businessmen in trouble with regulators.

HIs successor as attorney general, John Swallow, was also charged as part the investigation. Swallow, whose case is ongoing, is also accused of bribery and denies wrongdoing.

Shurtleff could have faced up to 30 years in prison if he had been convicted.

The U.S. Department of Justice investigated both men for bribery and other crimes but closed the case in 2013 without filing any charges. FBI investigators stayed on the case to help two Utah county attorneys who filed their own cases.

Salt Lake County District Attorney Sim Gill, a Democrat, has prosecuted Swallow, a Republican who resigned after less than a year in office amid a growing storm of investigations into his relationships with businessmen and allegations of traded favors.

Swallow denied wrongdoing and has pleaded not guilty to 13 charges, including bribery and tampering with evidence. His lawyer has asked a judge to dismiss the case, arguing that authorities wrongly obtained thousands of private communications between him and his previous attorney. A judge has not ruled on that request.

The move to dismiss the charges against Shurtleff was first reported Monday by The Salt Lake Tribune