(Lancaster) -- Former state House Speaker John Perzel is slated to plead guilty to charges related to the Pennsylvania Attorney General’s probe into the misuse of taxpayer dollars.

The specific charges to which Perzel will plead aren’t yet known, but will be related to the corruption investigation of House lawmakers and staff for using millions of tax dollars for campaign purposes.

Franklin and Marshall College political scientist Terry Madonna says to understand why the notoriously tough Perzel is taking a plea, look no further than his former staff: three former aides pleaded guilty and Perzel’s nephew is scheduled to do so tomorrow. "That puts the person charged in a pretty unenviable position, having to defend himself against the very people who were his or her top aides," he says.

Charges remain against five other Republicans for alleged involvement in the scandal. Some 15 Democrats were also charged. Perzel’s hearing is scheduled for tomorrow afternoon at the Dauphin County Courthouse.