Allentown Mayor Ed Pawlowski, who is running for a fourth term leading Pennsylvania’s third-largest city, has been charged in federal court in a pay-to-play scheme, his lawyer said. The charges were filed Tuesday but sealed, said Jack McMahon, Pawlowski’s attorney, adding that they will be made public Wednesday morning. It is the culmination of a lengthy investigation that came to light with an FBI raid on Allentown City Hall on July 2, 2015, and has since cast a pall over the city at a critical time in its revitalization.