This sort of thing happens whenever I run a Brindlewood Bay game for new players; it’s just part of getting used to the system, I think. I tell them two things: one, if they’re trying to find a clue, they can roll the Meddling Move. If they get a hit, I’ll look for a clue that could be a cause of death in the right context: for example, in Dad Overboard, I might take the clue ‘a small handgun, like you might find in a purse’ and say that he was shot with just such a small handgun, or that fragments of the shattered antique vase are found where he’s been bludgeoned, etc.
But before resolving the move, I’ll also tell the players that because of the way the system works, they’re less likely to find specific pieces of evidence or information (like a cause of death) and that the game will flow better if they tell me how they look for clues - I examine the body, I ask the Sheriff, etc - rather than what exactly they want to find out. I add that they may also find it more helpful to leave these details undefined until they’re ready to Theorise, and then have the flexibility to tell us what the cause of death was. If they’re receptive to that, they can still roll to Meddle, but the clue they find on a hit will take them in some other direction (like, “You’re not sure of the cause of death, but you do notice a bundle of stock certificates have been stuffed into his sock.”)