If the grandfather and grandson walking together in Sen. Rick Santorum's Internet ad look familiar, it could be because the same two actors are in a television ad that a third-party group is running in support of Santorum.

A spokeswoman for Santorum, R-Pa., has repeatedly denied any connection between Santorum and the group, Americans for Job Security.

The campaign for Bob Casey Jr. - the leading Democratic challenger in his 2006 Senate race - said Friday the coincidence is too much to be ignored.

"I think it raises a lot of questions," said Larry Smar, a spokesman for Casey, the Pennsylvania treasurer who is leading in polls against Santorum. "Someone isn't shooting straight."

Michael Dubke, president of the Republican-leaning third-party group, and John Brabender, Santorum's media consultant, each denied that the two sides had collaborated in any way. They each said it was a coincidence they used the same stock footage in their respective ads.

Both ads tout a plan by Santorum that he says would guarantee Social Security for those 55 and older.

"This is a piece of public stock footage which we've used in other ads before," said Brabender, whose group, Brabender Cox put together the ad for Santorum's Web site. "We have many senior shots in our ads, and certainly it's not in the least bit surprising that there could be shots that somebody else has access to as well."

Smar said the timing of the release of each ad is also suspicious.

The Internet ad started running on some sites on Nov. 25, Brabender said.

Americans for Job Security, which is based in Alexandria, Va., distributed its ad to television stations on Nov. 23 and it began running six days later, Dubke said.

You'll note that Americans for Job Security was recently investigated in Texas for using corporate money to influence Texas elections.  Charming bunch, this group.