【法】 无头公案

not have a clue intricate clue without a suspicion of know without a doubt without a break of without a grain of without a moment's thought without a name without a parallel without striking a blowing without a trace follow up a clue not have a clue provide a clue to intricate clue a case-by-case basis a distinction without a difference without a murmur without a doubt without a rival without a moment's thought