it's a lot harder to do this if your system/setting suddenly has rigid rules about all sorts of things, from travel, tech level, MAGIC, order of who you talked to, places you visited or observed, etc
in fact this is a big problem in investigations i rarely see brought up because it's covered by other sort of bandaid "rule of thumb" advice: what happens if your clue is in a place players swept and missed"
and those two schools of thought are "just give it to them" or "move the clue"




