Don't be silly. Point me to any article ... ANY PROOF AT ALL that no time was spent on any other person or persons. Your answer was vague in the extreme. Proof.
Let me clarify. If I misled you earlier, I apologize. After police locked onto DW, they spent no time pursuing any other leads. From that time on they ignored any evidence that didn't point at DW.
I named specifics earlier, so I won't repeat them.
Does that help? I don't believe I said they never spent any time checking out or interviewing anyone else.