In one case, two U.S. Marshals had been searching unsuccessfully for a key witness in a trial. McClairen was asked to assist and found the man in just two hours. In another investigation, he received an award for his role in locating Top Ten fugitive Holice Paul Black, who fled to Miami after killing a Chicago police officer.
A team player, McClairen did a great deal to support his colleagues, contributing in ways that didn’t show up in his own statistics but buoyed the overall success of the office. That included participating in dangerous raids, conducting surveillance, and even fixing Bureau cars.
He often supported larger investigations, too. For example, in the mid-1960s, he played a key role in a racketeering probe that took down Gil “The Brain” Beckley, considered organized crime’s top bookie in the country at the time. He also served for years as a highly regarded liaison with the Miami Police Department.
In October 1977, McClairen—nearing age 58—submitted a request for retirement.
“It has been a source of pride to have served my country through these years with the FBI,” he wrote. “I will always value the friendships I have made here and my loyalty will ever remain with the Bureau.”
McClairen retired on December 30, 1977. He died in Miami at the age of 85 on August 4, 2005.
Through his intelligence, integrity, and hard work during a time when there were few African-American agents, Leo McClairen served as an unheralded pioneer in the FBI. He paved the way for future generations of minority investigators and professional staff.