BOSTON -- Federal investigators may be closer to solving the world's greatest art heist, the theft of nearly $500 million worth of paintings from the Isabella Stewart Gardner Museum in 1990.

NewsCenter 5's Jim Boyd reported that on the morning after St. Patrick's Day 1990, two men dressed as police officers allegedly enticed security guards to let them enter the Isabella Stewart Gardner Museum.

The men allegedly tied up the guards and managed to steal art treasures now valued at $500 million.

Former antiques dealer and ex-convict William Youngworth has long been trying to convince investigators he can broker the return of the paintings for a price.

On "Primetime Thursday," Youngworth told reporter Brian Ross that the museum had long been targeted.

"It was on the short list of targets. It was loaded. I've even been there after hours," said Youngworth. "The place was a joke. I've been there at 2 o'clock in the morning."

Using state-of-the-art graphics animation, ABC recreated the crime, showing how thieves made their way through the museum, snatching Rembrandt's only know seascape, "The Storm On The Sea Of Galilee," from the wall and slicing the canvas from the frame. Thieves moved a few paintings down and removed Rembrandt's "Lady And Gentleman In Black, " -- again cutting the painting from the frame.

Ross said Youngworth continues to insist he knows where the artwork is and who took it. He is again trying to broker a deal, with conditions.

"And he says there's one last chance for the FBI to get the art back, but they have to cut a deal and the deal is that nobody goes to jail, essentially," said Ross.

"Primetime Thursday" can be seen on Ch. 5 Thursday at 10 p.m.