Richard Schlesinger (48 Hours Correspondent)

Everyone in Springfield, Illinois knew Mark Winger's story.

It was heroic and heartbreaking.

But Detective Doug Williamson had never believed one word of it.

I was argumentative.

I pointed out what we call red flags, pieces that don't seem to fit.

At first, Williamson couldn't even convince his own partner, Charlie Cox, that Winger was a murderer.

But Cox says he started getting suspicious when Winger kept showing up here at the police station.

A few months after the murder, Winger came by.

to ask for his gun back.

I released the gun back to Mark, and we sat and talked for about a half hour.

What did you talk to him about?

Just things in general.

He was wanting to know how the case was going, and as far as I was concerned, he should have just accepted it was closed.

Winger denies it, but Cox remembers him dropping by a second time, this time to say he was getting remarried to his daughter's new nanny, whom he had hired just five months after Donna's murder.

And he kept coming in.

I kept feeling like he was trying to find out if we were checking into anything.

And I went back to Doug and said, something's wrong here, big time.

Winger's behavior was making Cox believe that his partner had been right all along.

He thought about the problems in the case, like that note in Harrington's car.

And now Cox also wanted the case reopened, fearing that Mark Winger had duped the police.