INQUIRER: The perfect crime has long been a concept best left to Hollywood writers, not East Coast goodfellas. But this one was close. As St. Patrick’s Day came to an end 23 years ago, two men dressed as police got into Boston’s Isabella Stewart Gardner Museum, cuffed the guards to a basement pipe, and made off with 13 works of art, including ones by Rembrandt, Vermeer, and Degas. The loot, valued at $500 million, made the heist the largest in U.S. history. On Monday, the FBI shone a new spotlight on the old crime, one with a local twist. The stolen artwork, agents said for the first time, had once been spotted in Philadelphia – and might even still be here. Special Agent Geoff Kelly, the lead investigator for a decade, said agents had confirmed that one or more of the missing works was offered for sale here a dozen years ago. “We don’t know if the deal was ever consummated,” Kelly said in an interview, “but we were able to corroborate the information that they were seen in Philadelphia – it appears to me, more than once.” MORE