Here's some general blacklight ideas/advice: https://www.constructedadventures.com/how-to-build-a-treasure-hunt/2018/2/17/using-blacklights

I'm a little confused at the structure of your hunt. Will your wife be checking in with your kids to get each location? Are you planning to create a murder scene for each clue?

Seems to me like solving a single murder is plenty of setup work for you, and a single crime scene could contain all of the clues needed. I've done a similar hunt using one of these. Each puzzle solved gives a combination to one of the locks, and the hasp can be opened once all of the locks are removed. Once the puzzle locked behind the hasp is solved, your wife can save the would-be victim.