Perhaps this will explain what sets this thief to his task:

Harry drank five beers into the 12-pack and it was only 9:30. He let go a tremendously satisfying belch which began at the lowest portion of his bulging stomach and worked its way upward with increasing speed to fly from his lips. He found that if he moved his mouth in different shapes he could change the tone of his belch. He burped in B-flat, then reached to open his sixth can.

He took a drink of the new beer. With the remote control, he turned the volume up on the television. Pretty Boy Maddox was fighting The Executioner on World Television Wrestling. The fans screamed, the announcers going wild but Pretty Boy didn't have a chance, Harry knew.

Something wrong with the picture. All night, shadows flickered in and out of the screen. Wavy specters tracked across the glass as if the TV was in some way possessed. The damn TV was almost new and he'd paid the cable on time at the start of the month. One of the only bills he paid on time.

But this man seems to contradict Marilyn's description. He's not thin and ravaged. Marilyn needs to have her eyes examined, perhaps, or this "life" is from a time far distant to the robbery. Who knows when Harry sat drinking beer. Would this limited life be enough to set Harry off?

Another teacher of mine said you can't ask why one character likes another: "It's the muscle in his thigh, it's because of the way he parts his hair." Such things are overdetermined; Freud tells us that, as I've said. Perhaps Harry has given up beer for something else. Perhaps the thrill of being caught attracts him. Perhaps his name is not Harry at all?