"The most audacious and lucrative art scam in U.S. history," 60 Minutes' Anderson Cooper says of the 63 artworks forged by a Chinese immigrant in Queens and sold largely through Knoedler Gallery in New York for $80 million.

Anderson sat down with Jack Flam, the Robert Motherwell expert, and a forensics expert, who expose the details that helped lay open the scam.

"The smoking gun was the red paint on the edge," said the forensics expert about a fake Motherwell work. That particular pigment was available on the market years after Motherwell supposedly created the painting.

The experts explain there were quite a few more "obvious" signs that the paintings were fake, including the misspelling of a signature.