When Jerry and Rita Alter died, a painting was found in their bedroom in the tiny town of Cliff, NM, and then was sold to an antiques dealer along with the rest of their effects for $2000. The dealer soon discovered that the painting was an original Willem de Kooning worth in the neighborhood of $150 million. The painting had been stolen in a daring raid from a Tucson museum in 1985 and a recently discovered piece of evidence shows the Alters were in Tucson on the day before the theft.

The next morning, a man and a woman would walk into the museum and then leave 15 minutes later. A security guard had unlocked the museum’s front door to let a staff member into the lobby, curator Olivia Miller told NPR. The couple followed. Since the museum was about to open for the day, the guard let them in. The man walked up to the museum’s second floor while the woman struck up a conversation with the guard. A few minutes later, he came back downstairs, and the two abruptly left, according to the NPR interview and other media reports. Sensing that something wasn’t right, the guard walked upstairs. There, he saw an empty frame where de Kooning’s “Woman-Ochre” had hung. At the time, the museum had no surveillance cameras. Police found no fingerprints. One witness described seeing a rust-color sports car drive away but didn’t get the license plate number. For 31 years, the frame remained empty.

Earlier this year, WFAA made a short documentary film about the Alters and the heist.

(If you don’t want to watch the entire video, at least check out the bit starting at 18:00 where the painting is given back to the museum and authenticated…that is something you rarely see on video as it happens.)

Adding to the mystery: the couple obviously never sold the painting but they retired early, travelled the world, and left a $1 million inheritance, all seemingly beyond their means as public school employees.

Something else doesn’t add up. Jerry and Rita Alter worked in public schools for most of their careers. Yet they somehow managed to travel to 140 countries and all seven continents, documenting their trips with tens of thousands of photos. And yet, when they died, they had more than a million dollars in their bank account, according to the Sun News. “I guess I figured they were very frugal,” their nephew, Ron Roseman, told WFAA.

Hmm, where did they get all that coin?