The detective knew now that he was dealing with a murderer.

Maybe the detectives knew more than they were letting on.

The detectives clearly didn't know what to make of the idea.

The detective didn't know about the medical examiner's report yet.

When he reached Philadelphia, the detective knew nothing of its significance.

The detective knew at once that some one in the house had opened it.

In addition, he said, detectives do not know how the fire was started or by whom.

There are still ways to cheat, but a detective knows where to start.

The detectives hadn't even known the two men were acquainted.

And the detective knew it could have been much worse.