Released in 1989 by C.M. Ralph, Caper in the Castro is a point-and-click mystery game taking inspiration from the LGBT community. The story follows lesbian private detective Tracker McDyke as she attempts to find the kidnapped drag queen Tessy LaFemme. As she investigates, Tracker uncovers a deeper mystery involving a plot by Dullagan Straightman to poison the alcohol supply of a gay bar with a fast-acting and incurable disease.
Development on the game began in 1988, shortly after Ralph moved to San Francisco. Finding a place in the state's LGBT community, Ralph wanted a way to give back, and began developing the game in Macintosh HyperCard. In early 1989, Caper was released as charityware via an LGBT BBS, with an in-game message asking that players donate to HIV/AIDS relief charities.
Given the limited release the game saw, it was long thought that the game had been lost, despite being an early, if not the first, example of LGBT themes in video games. However, both the original BBS release and the game's subsequent retail version were found in 2017 and archived on the Internet Archive.
In late 1989, Ralph created a new version of Caper with all direct references to LGBT topics removed, in hopes of getting the game published. That same year, Heizer Software licensed the game under the name Murder on Main Street, distributing it via mail order catalog for a number of years.