Not much is known about the origins of Matthew Slade, Private Investigator. However, an original Playbill on Digital Deli proclaims:
"Pacifica Players Present: The Starlight Mystery Theater featuring the adventures of William Wintersol as Matthew Slade: Private Investigator"
The stories revolve around Mathew Slade (San Francisco Private Investigator), his secretary Lorretta Jones (known as "Jonesy") and Sgt. Sid Donelli of the Homicide Bureau.
The cast members include: William Wintersol as Mathew Slade, Sylvia Wheeler as Jonesy and Norman Belkin as Donelli.
The each show ran for 30 minutes. It was syndicated in the 1960s, and also broadcast as part of the Armed Forces Radio Service (AFRS).
It appears that 13 episodes were broadcast of which 10 are known to have survived.