Lets put this situation in your shoes..
You know that you dont have enough evidences to prove someone that he/she guilty and that most of your conclusions are just opinionated ideas that you've come up with. Will you still push on? Will you still force your ideas into the crime? Tricking every person and making them think that your ideas are facts?
Is it right to trick every person? No, generally... The burden of proof is on the accuser, that is the standard custom. The harder it is to prove guilt, the sneaker the wrongdoer had to be. It's an economic tradeoff almost.