A top bank regulator pushed back Wednesday against a group of Senate Democrats who have been seeking to have the regulatory agency work with states and the Justice Department in their investigation into residential mortgage-loan-servicing and foreclosure processes. “In terms of cooperation, we are careful not to interfere with ongoing negotiations with the DOJ and state attorneys general,” David Wilson, a deputy comptroller at the Office of the Comptroller of the Currency, told lawmakers at a Senate Banking Committee hearing. Wilson added that the OCC is coordinating with the Justice Department and states. His comments came after a group of Senate Democrats sent a letter Tuesday to the OCC calling on the agency to participate with states and the Justice Department on mortgage-servicer settlement talks.