Analysis of Confession

A sleuth like Pinkerton or Burns
Is told that there has been a crime.
He runs down clues and leads, and learns
Who did the deed, in course of time.
It's just the other way with me:
The first thing I am sure of is
The criminal's identity,
And then I learn what crime was his.

When Son comes up with hanging head
And smiles a certain kind of smile,
When he's affectionate instead
Of playful; when he stalls awhile
And starts to speak and stops again,
Or, squirming like a mouse that's caught,
Asserts, "I am a GOOD boy," then
I look to see what harm's been wrought.