Make him psychic or something?

Well, that's just it - then he's not Sherlock Holmes, he's some other character. There are plenty of those about already.

He's still got to make observations, and then make his deductions; but what's he going to observe that the police overlook? Perhaps he can draw conclusions from seemingly unrelated facts that the police don't connect? But wouldn't that make the police look stupid? I dunno. Wait and see...