I would say Ralph Dibney, but it's more based on rep and the purpose of his character more than any proof from cases he's solved in canon. I love the Question, but he has been shown to focus on more existential matters or complicated conspiracies rather than actually getting down to solving crimes. The shame is that Bendis's Leviathan event brought together all the top tier detectives only to have them bickering in Batman's kitchen and not actually solving anything.
Lois Lane also deserves consideration in this category.