The date for that version is approximate but based on a playtest request from the author, that appeared in Your Sinclair issue 34. The authors were 14 when they wrote the game.
Although it was playtested, the adventure was never actually released back in the day. The initially archived versions are likely to have been sourced from a playtester. In 2022 author Edward Toovey finally released the a completed Spectrum 48K version of the game; downloadable here.
Originally envisaged as part of a trilogy, with a three-part prequel (Murder, Mystery and Suspenders) and a sequel (The Feud). Work on the prequel game was started but never finished; although the first part of the prequel was also released in 2022 as A Case of Murder.
In 2023, Edward Toovey returned to the game, producing a new revised version using DAAD. This version is available in both a 48K text-only version and a 128K version with occasional graphics. There are versions for Amiga, Amstrad CPC, Amstrad C64, Atari ST, C64, C16/Plus 4, MSX 1, MSX 2 and PC. Some platforms have a choice of text-only or graphics. See here for details.
[+] Users who have solved this game
[+] Users currently playing this game
The solution for the C16/Plus4 also works for the Spectrum 128k; the 48k solution is a little bit different.