After the 1947 UFO sighting, Arnold became famous "practically overnight". Arnold's daughter would later recall the family receiving 10,000 letters and constant phone calls.
Arnold was contacted by Raymond A. Palmer, editor of fringe/sci-fi magazine Amazing Stories, who asked Arnold to investigate the story of two harbormen in Tacoma who reportedly possessed fragments of a "flying saucer". Palmer sent $200 to fund the investigation.
On July 29, Arnold interviewed a harborman who claimed that one of the objects "began spewing forth what seemed like thousands of newspapers from somewhere on the inside of its center. These newspapers, which turned out to be a white type of very light weight metal, fluttered to earth". The harborman claimed the craft emitted a substance resembling lava rocks that fell onto his boat, breaking a worker's arm and killing a dog.
Arnold interviewed Fred Crisman, an associate of the harborman, who reported having recovered debris from Maury Island and having witnessed an unusual craft. Crisman showed "white metal" debris to Arnold, who interpreted it as mundane and inconsistent with the harborman's description.
Arnold contacted the Air Force, and two officers soon arrived to investigate. The officers conducted interviews, collected the fragments, and took off in their plane to return to base. In the early hours of August 1, the two officers died when the B-25 Bomber they were piloting crashed outside of Kelso, Washington on their way back to California.
Writing in 1956, Air Force officer Edward J. Ruppelt would conclude "The whole Maury Island Mystery was a hoax. The first, possibly the second-best, and the dirtiest hoax in the UFO history."