I can't believe someone did it, and that someone was SEGA decades ago HEEEYOOOOO! Jokes aside, Sonic appears to be dead and SEGA did actually release this. Time to flex some reading, deducing and lore crunching muscle.

The Murder of Sonic the Hedgehog
A brand new Sonic experience from the minds of the Sonic Social team: The Murder of Sonic the Hedgehog is a visual novel, point-and-click adventure! It's Amy Rose's birthday and she's hosting a murder mystery party on the Mirage Express. When Sonic becomes the game's victim, everyone is off to get to the bottom of things. However, something feels a bit off - is this really an innocent game or something more sinister afoot?
There are more suspects to question on the impossibly proportioned train. Tails and Lobe continue through the casino and lounge cars. Do they have enough to collar the culprit?
Tensions on the train are high but one question has risen to the forefront. Just how do they get off that thing?