HARRISBURG — Pennsylvania Revenue Secretary Stephen Stetler resigned hours before state prosecutors are expected to announce more charges in their ongoing public corruption investigation.

The chief of staff to Gov. Ed Rendell, Steve Crawford, said Stetler's letter was received today.

The attorney general's office won't say if Stetler is among those to be charged, and Stetler's lawyer didn't immediately return phone messages seeking comment.

Attorney General Tom Corbett planned an afternoon news conference to disclose additional arrests in a three-year investigation into the Legislature's campaign and financial practices.

Stetler had been a leading campaign strategist for the House Democrats while representing a York district.