By Tony Romeo

HARRISBURG, Pa. (CBS) — A former Philadelphia man who has exhausted his appeals is now set to be executed in October.  But his attorney is seeking to halt the execution based on new allegations that his client was sexually abused by the victim.

The execution warrant for 46-year-old Terrance Williams is the sixteenth signed by Gov. Tom Corbett since taking office.  But one thing making this different is that Williams has already had several appeals turned down, and his execution may actually take place.

However, his attorney, Shawn Nolan, says he is undertaking a new appeal based on fresh evidence that Williams was sexually abused as a teenager by the man he killed in Philadelphia 28 years ago.

“We think it’s a very strong issue, particularly in light of the fact that the jury that originally sentenced Mr. Williams to death did not know this information, and those jurors have now said that it would have changed their verdict — that they would not have sentenced him to death,” Nolan tells KYW Newsradio.

If the new appeal is not successful, or barring some other development, Williams is set to become the first man executed in Pennsylvania since Gary Heidnik, in 1999.