David Thomas Block, known as Dave, was last seen in Washington, D.C. on May 1, 1995. He was 35 at the time, described as a white male with blond or strawberry-blond hair, blue eyes, standing between 5 feet 8 inches and 5 feet 9 inches and weighing about 154 pounds.

His disappearance crosses international lines: although his last known location was in the United States, he was reported missing to police in Swastika, Ontario. The year before he vanished he had been seen in Newfoundland, Canada, and the reasons for his travel between provinces and into the U.S. have not been publicly detailed. He was known to be experiencing unspecified mental health problems, and relatives have provided DNA reference samples to assist identification if needed.

Decades later the case remains an active missing person investigation with few public leads and no public resolution. If anyone saw David in Washington, D.C., or knew where he was traveling or who he was with around spring 1995, please share what you remember.