PROVIDENCE, R.I. — An opponent of Rhode Island Secretary of State Ralph Mollis in the lieutenant governor’s race called Wednesday for him to step aside from an investigation into potential lobbying violations related to 38 Studios because the probe comes too late.

Cumberland Mayor Dan McKee said in a letter hand-delivered to Mollis’ office that Mollis declined two years ago to investigate the lobbying of Rhode Island elected officials “when it was obvious” that 38 Studios had lobbied.

He said the lack of an investigation allowed attorney Michael Corso and others to conceal the “true nature of their involvement” in pushing the program under which ex-Red Sox pitcher Curt Schilling’s video game company got a $75 million state-backed loan.

Mollis scheduled a hearing for Tuesday after media reports raised questions about whether Corso lobbied for the loan guarantee for the now-bankrupt company without registering as a lobbyist and filing the proper reports. That hearing was continued to next week.

Mollis said in a written statement that he began his probe when he became aware of potential violations, and that he intends to continue it. He accused McKee of trying to revive a “faltering campaign.”

Corso had a consulting agreement with 38 Studios that was dated 2011. Corso also offered his office for a 2010 meeting attended by ex-House Speaker Gordon Fox and Schilling, Fox has said.

“This state deserves a fully independent investigation that includes a review of the failings of the Secretary of State’s Office,” he wrote. “Please do what is right for Rhode Island. Step down from the investigation and allow the state to retain a truly independent counsel … an objective professional who is not hired by your office and who is not a State House insider.”

Attorneys for Corso said in a June 2 letter to Mollis’ office that the secretary of state has produced no evidence of a lobbying violation. A finding of an intentional violation could bring a fine of up to $2,000.