Rep. Mari Manoogian (D-Birmingham) made the allegations in a statement. Marino was removed from his committee assignments Wednesday.
"I had a relationship that ended well over a year ago with Representative Amara Manoogian. She served on a committee that I chaired. I regret the fact that I went along with her request to not disclose the prior relationship to the Speaker," Marino's statement read. "However, I will be clear: the insinuations made are nothing more than politically motivated character assassination that I am confident will conclude as a waste of the public's time. I look forward to fulfilling my duties and maintaining the trust I've worked so hard to build during my seven years in public office."
A spokeswoman for Michigan State Police said they are looking into a complaint filed against Marino which they received late Tuesday, but would not provide further details.