Police in Albuquerque, New Mexico were surprised to discover a portfolio containing 72 prints by the Native American artist Alfred Morris Momaday in a former meth lab, the Guardian reports. According to the officers, the $33,000 prints were probably stolen.

An officer at Albuquerque Police Department was performing a final check of the derelict building before boarding it up, when he stumbled upon the artworks.

Although police aren’t certain that the art was stolen, the location of the discovery is suspicious. Tanner Tixier, a spokesman for the APD told the Albuquerque Journal “The house where it was found would not be conducive to the type of environment where you’d find $30,000 worth of art.”

The officer who found the prints brought the portfolio to the Albuquerque Museum of Art and History for safekeeping. Curator Andrew Connors remarked that it is unlikely that the prints were taken from a private collection because the portfolio includes several editions of the same four prints. He speculated that “They may have been stolen out of a warehouse or a back storage building behind a gallery or an artist’s estate.”

Alfred Morris Momaday’s son, the Pulitzer Prize winning author N. Scott Momaday, discovered that some of his belongings, including a computer and boxes of his father’s work, may have gone missing from his Santa Fe a storage facility in December. He chose not to report the missing items because he wasn’t sure what had gone missing. His assistant explained that Momaday junior’s father “had a vast amount of work.”

Alfred Scott Momaday is one of the most famous Native American artists. His son described him as “A full-blooded Kiowa Indian and a really primitive-style painter … He went on to make a sound reputation.”