Since its introduction in the 1940s, Clue has proven—over and over again—that murder can be quite fun.

The game, which also inspired the 1985 cult film of the same name, centers on deducing who killed Mr. Boddy (known as Doctor Black in the original British version). The first player to guess the weapon, suspect, and room of the crime, tucked away in a small envelope in the center of the game’s board, wins.

Board game lore has it that Englishman Anthony Pratt refined the idea for the game while on night patrol during World War II. He described it as a variation of a murder mystery parlor game he used to play with friends, and saw it as a way to reinvigorate his peers' social lives.

''Between the wars,'' he once said, ''all the bright young things would congregate in each other's homes for parties at weekends. We'd play a stupid game called Murder, where guests crept up on each other in corridors and the victim would shriek and fall on the floor.’' The war—and its associated air raids and blackouts—put a stop to these regular gatherings. “It all went, 'Pouf!' Overnight, all the fun ended," he later recalled. "We were reduced to creeping off to the cinema between air raids to watch thrillers ... I did so miss the partying and those awful games of murder." 

Pratt wasn’t necessarily a dark soul. Mystery and detective themes were having a moment in popular culture, as authors Agatha Christie's and Raymond Chandler's sleuths captured the public's imagination. Party games, like the one that inspired Pratt, were commonplace; legions of children and adults were trying to follow in Sherlock Holmes' footsteps. (Early versions of Clue's game boxes touted it as the “great detective game” and featured a Sherlock character.) 

In 1944, Pratt applied for a patent for his game. (His application reportedly boasted illustrations drawn by his wife, Elva.) According to Ann Treneman, author of Finding the Plot, Pratt initially called his game “Murder,” inspired by the era’s favorite mystery genre. The game eventually went by Cluedo in the United Kingdom, a spin on the Latin word for play, "ludo," which was also the name of a then-popular game in Britain.

Pratt’s board was “marked out to depict the ground floor of a house” with eight or 10 rooms, according to his patent. The cast of 10 characters included a Doctor Black, Mr. Brown, Mr. Gold, and Miss Grey. There was also a Rev. Green (who was defrocked when the game came to America), a Nurse White (she became a Mrs.), and a Colonel Yellow, who was renamed Colonel Mustard. The weaponry was far more grim, and included a bomb, a syringe, and poison. His map had a layout similar to the one known by American fans of the game, but included a “gun room” in between the lounge and the dining room. In the original patent, Pratt planned to have his victim be a rotating character. But by the time it got into production, Doctor Black had become the permanent victim.

Pratt sold his design to Waddingtons, a British company that also published Monopoly in England, and by 1949, production for Cluedo was underway. At first, according to Treneman, Cluedo sales were weak, leading Pratt to sign over all overseas royalties to the game for £5,000—that's around £124,000, or $200,000, today. By doing so, Pratt missed out on millions of dollars in royalties. (The British patents eventually lapsed, too, which means the royalties from domestic sales disappeared as well.)

Initially, the sum he earned allowed Pratt to return to his first love: music. As a young man, Pratt had dropped out of school in order to play piano aboard various ocean liners. Using his Cluedo funds, he began touring with his cousin Paul Beard, who was then the leader of the BBC Symphony Orchestra. But the money soon ran out, and Pratt was forced to return to his pre-Clue work as a patent clerk—and to fade into relative obscurity. 

In later years, Pratt's daughter Marcia admitted that her parents almost never discussed the iconic game her father had invented. “My mum was angrier than he was about it,” she revealed in 2009. “In those days you didn’t go to financial advisers or agents. Ordinary people like us didn’t even know they existed.” Her father was more at peace with the decisions he had made: “He felt we’d had a good time for a few years on the back of the game. He didn’t court the recognition and we weren’t penniless but I can’t help thinking the money would have made my parents’ final days so much more comfortable.”

In 1996, as part of a celebration for Clue's 150 millionth sale, Waddingtons executives attempted to track down Pratt. They could not find him. Authorities began an official search, even establishing a hotline for tips, according to The New York Times

Ultimately, Pratt was located—in a cemetery. An undertaker called in to report that two years prior, Pratt had died peacefully at the age of 90. Miss Scarlet (in the Billiard Room, with the Candlestick) was exonerated.  

Nearly 70 years later, Clue remains as popular as ever, remaining relatively the same in terms of technical game play as it was in the '40s (although illustrations have been swapped out or updated along the way to make it feel more "contemporary.") Today, much like its Parker Brothers sibling Monopoly, a wide variety of Clue games now exist, including sets paying tribute to The SimpsonsFamily GuySeinfeld, and Scooby Doo, just to name a few.