rotating in my mind:
- the book genre "cozy murder" (murder mysteries set in cozy locations in which the detective is an amateur sleuth and violence occurs offstage)
- the game genre "cozy games"
- cozy murder games??

rotating in my mind:
i've had an idea for a columbo style point and click for ages, i think that's what this is describing
you're describing Overboard!: https://www.rockpapershotgun.com/overboard-review
9/10 chance there's a sound novel that already meets this premise.
Around when Stardew came out I thought "what if Stardew/Harvest Moon but at new game it picks a random townsperson to be a murderer and you have to figure it out while also farming and making friends and whatever" and then recently I think basically that exact game came out? I haven't checked it out because I've become pretty burnt out on life sims since so no clue if it's any good...