Lester Holt

He said she'd recently been taking the supplement called creatine in the hopes it would help with fertility.

Veteran detective Harry Lutton understood the late wife's emotional agony.

She's trying to have another child.

And that's a lot of stress on a woman when they're trying to have children and they can't have children.

Could Autumn's distressed state of mind have led to suicide?

Detectives had to consider that as a theory.

But cyanide, that's an unusual way to kill yourself.

And it's a hard-to-get poison.

How could Autumn have gotten her hands on it?

Well, we looked into the labs that, you know, where she worked.

She didn't work in a lab.

She worked with patients.

She was a clinic doctor, right?

She was working hands-on.

Yes.

But there were other labs at the medical complex, labs stocked with poisons, including cyanide.

Maybe Autumn wandered into one of those.

Detectives pulled hospital security cam footage from that last day, and here's what they saw.

That's Autumn as she's getting ready to leave work.

She goes up a set of escalators, disappears for roughly six minutes, before coming back down and heading home.