is using a carefully devised psychological strategy

her interrogation of the Green River Killer, Gary Ridgway.

Her goal is to get him to confess

to 44 unsolved homicides, where no physical evidence exists

that could link him to the crimes.

O'Toole is recognized as the FBI's leading expert

in the area of psychopathy.

Many of these men kill women.

They may maim them and sexually assault them,

but they love talking to women.

They love talking to people that are good interviewers

and that will listen.

My strategy was to get him talking

and to have him do most of the talking.

How are you this morning?

Pretty good.

Slept real good.

A little tossing and turning, but pretty good.

Good.

Good.

I'm glad to hear that.

I would also sit very close to him

so that I could maybe touch his elbow

and say, Gary, tell me what it feels like.

NARRATOR: The questioning goes on for weeks.

Some sessions last for hours.

Turn him off, and he will not talk,

and your goal is to keep him talking.

And finally, something within Gary Ridgway cracks.

Bit by bit, he starts talking.

(INAUDIBLE) that it started at an early age,

but sex and hurting the-- hurting the woman.

And he loved being able to talk finally after all

these years, and in doing so, he kind of walked us down the path

of all of his murders.

At one point, Gary referred to himself

as something like the lean, mean killing machine,

and he was very efficient, like a machine.

Explain that process to me.

Let's say she's already in the car.

I'm driving down the road.

So I whipped out my ID, and my ID

would be my-- I'd put my finger over my driver's

license to hide my name.

Then on the opposite side was pictures, a picture of my son.

They would know I was probably a normal person.

But you were really using your son as part of your ruse.

The girls would think Ridgway was a kind family man.

They had no idea they were setting

off with a serial killer.

And he would drive up to them, and sometimes he'd

even have his son's toys in the front seat,

and that would be a very effective ruse

to convince these women that, hey,

I can't be that serial killer.

I've got my little boy's toys in the car.

He was a very normal, kind of vanilla-type looking person,

and there was nothing that stood out about him, not dangerous.

He could have been anybody living next door.

He was anybody living next door.