Art Heist

Permanently Closed - You're part of an elite group of thieves whose mission is to steal a rare piece. Mr. DuPont is an avid collector who has a fascination for unattainable art. His M.O. is replacing an original piece with a forgery so it's never even known to be missing. He arranged a heist to be completed by another team, but their mission was unsuccessful. They had just enough time to stash the forgery before being captured. You've been hired to retrieve it, replace the original that’s being displayed, and secure any evidence that could link back to Mr. DuPont. Question is, which piece is it, and where was the forgery stashed?