The book is a compilation of multiple crime riddles. It was most likely published in mid 90s to early 2000s. I’m pretty sure it was a dark purple color and I vaguely remember a magnifying glass on the cover. Oh, and it also contained one mystery involving a murder around a maypole.
Have you eliminated Encyclopedia Brown, by Donald Sobol?
If it’s not that, maybe one of the True Lies or Stories to Solve books, both by George Shannon.
There was another series from the 80s/90s that was written by an author with the last name of Lee, but I can’t remember the titles or his(?) first name.
OH MY GOODNESS!!
While your tip wasn’t THE book I was looking for it did lead me down an amazon rabbit hole where i did indeed find the book!!
It’s called “Crime and Puzzlement: My Cousin Phoebe”!! Thank you so much!!!