Lester Holt

Pittsburgh senior investigators were en route to talk to Robert Ferrante.

Did he have any idea how cyanide found its way into the bloodstream of his late wife?

Coming up, a husband's theory of how and why his wife died.

So what do you say?

Why would she do this to herself?

What was he suggesting?

And did he know something that police didn't?

Five days after doctors turned off the machines on Dr. Autumn Klein, Pittsburgh police detectives made their way to the three-story brick house where she made a home with her daughter and husband, medical researcher Robert Ferrante.

Veteran detective Jim McGee took the lead.

Ferrante greeted him and his partner.

We start talking to him and what he can tell us about what happened to his wife at that point.

Ferrante told the detectives how his wife had arrived home that night a little before midnight.

and how she came through the door and just collapsed on the floor.

He then recounted what he told 911.

He thought his wife had suffered a stroke.

The detectives informed him he was wrong about that.

We asked him if he knew that his wife died of cyanide poisoning.

So what did he say?

He kind of gasped and said, why would she do this to herself?

Why would she do that to herself?