A Danish antiques dealer named Ittai Gradel noticed a particular seller repeatedly listing valuable items for sale online at rock-bottom prices. WSJ's Max Colchester recounts how Gradel's sleuthing would eventually reveal a major antiques heist involving stolen British Museum antiquities.  Further Listening: -How Investigators Cracked a $3.4 Billion Crypto Heist  -Is This Painting a Masterpiece? AI Is On the Case  Further Reading: -How an Academic Uncovered One of the Biggest Museum Heists of All Time  Learn more about your ad choices. Visit megaphone.fm/adchoices