A Revolutionary War veteran turned outlaw, Mason made the transition from frontier militia captain to river pirate during a period when the lower Ohio and Mississippi were barely governed and easily exploited. His gang operated across a sprawling geography — Cave-in-Rock, Stack Island, the Natchez Trace — preying on travelers and river traffic at a time when such routes were lifelines for westward settlement. What distinguishes his case historically is the gap between his documented record of service and the sustained criminal enterprise he later commanded, a contrast that has made his motivations difficult to resolve.

His case remained open for decades partly because investigators were searching for multiple offenders — it wasn't until 2001 that DNA evidence confirmed the East Area Rapist and the Original Night Stalker were one and the same man. Operating across California over more than a decade, DeAngelo accumulated victims across three distinct criminal phases: burglaries, sexual assaults, and murders, often taunting those he targeted and the law enforcement pursuing him. His eventual identification in 2018 through genealogical DNA analysis marked a turning point in how cold cases of this scale could be solved.