“Carmen said something to me on that sidewalk before she left.” I was not shouting.

I have gone over that night many times and I did not raise my voice once, and that is not a virtue, it is that I could not get enough air.

“She said, ask your mother what she got in the mail.”

Nothing.

“Mom.

What did you get in the mail.”

And my mother — seventy-one years old, in a car, in her own driveway — said: “Come inside and I’ll make coffee.”

Which is, I have come to understand, the most complete confession she was capable of making that night.

Part Four: The Cheapest Test in the Building

We started trying in the spring of 2012.