The 1948-49 series Box 13 featured a former newspaper reporter, Dan Holiday, now a novelist. He had become a detective/adventurer, advertising for tips sent to his classified-ad box, to dig up plots for his works of fiction. The newspaper’s main role is carrying his classsified ad, but he stays in touch.
In a November 1948 episode titled “Suicide or Murder” in the Old Time Radio Researchers Internet Archive collection (although there is no hint of suicide in the actual story), writer Holiday finds a note in Box 13 from the mother of a recently deceased Evening Record reporter. He was a war veteran and Nuremburg Trials observer with a Distinguished Service Cross whose death was attributed to a drunken bar fight. The mother doesn’t believe it and neither does Holiday, played by Alan Ladd.
He finds out from the dead reporter’s editor that he was working on a “big story,” but had been secretive about it. Holiday and the editor, an old friend, search through the dead guy’s desk and begin to unravel the story. The young reporter, less than six months on the job, had been sent off to a Carribean island on a “Latin American neighbors” feature assignment. (Some budget that Evening Record had in 1948! But Holiday and the editor treat that much as routine. A waterfront bartender also is impressed by Holiday’s expensive suit and tie, so maybe journalist and novelists we’re making good money back then. Or at least radio script writers led the audience to believe such a thing.)
Eventually, after another murder, Holiday finds a war-criminals-escape-to-Caribbean clue in the reporter’s notebook and sets off on a search for missing film and the murderers… and the film turns up, quickly followed by a mysterious character with an accent and $10,000 to spend for negatives. The police and a happy ending can’t be far behind.