The Devil Knows You're Dead by Lawrence Block

don’t think anyone’s tried to argue that your brother was behaving rationally.”
    “Even so, Matt. Even so. Look, speaking of the gun. The murder weapon was a nine-millimeter pistol, right? The bullets they dug out of Holtzmann were nine-millimeter, and so were the casings in George’s pocket.”
    “So?”
    “So George had a forty-five.”
    “How do you know?”
    “I saw it.”
    “When?”
    “Maybe a year ago. Maybe a little less than that. I came looking for him, I had some stuff for him, and I drove around until I found him. He was in one of his usual spots, near the entrance to Roosevelt Hospital.” He drank some coffee. “We walked back to his room so he could stow what I’d brought, clothes mostly, and a couple of bags of cookies. He always liked those Nutter Butter cookies, with the peanut-butter filling. From the time we were kids, that was his favorite kind of cookie. I always brought him some whenever I went looking for him.” He closed his eyes for a moment, opened them and said, “We got to his room and he told me he had something to show me. The place was a mess, piles of crap everywhere, but he knew right where to look and he moved some junk out of the way and came up with a gun. He had it wrapped in this filthy hand towel, but he unwrapped it and showed it to me.”
    “And you were able to identify it as a forty-five?”
    He hesitated. “I don’t know a lot about guns,” he said. “I’ve got a revolver I keep at the store, a thirty-eight, it sits on a shelf under the cash register and I don’t even touch it from one month to the next. We’re on Kings Highway west of Ocean Avenue, household appliances, we’ll sell you anything from a Waring blender to a washer-dryer, and there’s not a whole lot of cash comes over the counter. It’s all checks or plastic nowadays, but they’ll hold up anything, they smoke a little crack and they can’t think straight, and if the cash register’s empty they’ll shoot you to make a point. So the gun’s there, but I pray to God I never have to use it.
    “It’s a revolver, I don’t know if I mentioned that. The gun George showed me wasn’t, it didn’t have a cylinder like mine. It was L-shaped, rectangular.”
    He sketched its outline on the tabletop. I told him it sounded like a pistol, but how did he know it was a forty-five?
    “George said that’s what it was. He called it a forty-five-caliber pistol. What was the other phrase he used? A military sidearm, that’s it. He said it was a government-issue military sidearm.”
    “Where did he get it?”
    “I don’t know. I asked him and he said something about carrying it in Vietnam, but I don’t believe he brought it back with him. I think he may have had one like it over there. My guess is he found this one or bought it on the street. I don’t know if it was loaded or if he even had any bullets for it. The cops turned up people from the neighborhood who said he used to carry a gun and he’d take it out and show it around. Maybe he did. Life he led, I can see him carrying a gun for protection, even using it to defend himself. But why would he have to defend himself from a man making a phone call? And anyway, you can’t shoot nine-millimeter bullets out of a forty-five, can you?”
    “What happened to the gun?”
    “The one I saw? You got me. It wasn’t on him when they picked him up. They didn’t find it when they searched his room. They say George told them some story about throwing it off a pier into the Hudson. They sent divers down and came up empty, but who even knows if they had the right pier. You want to know what I think happened?”
    “What?”
    “George threw his gun in the river months ago. One reason or another he decides it’s not safe to carry it and he ditches it, and then when they pick him up and ask him what happened to the gun, he says he tossed it. He can’t say when because he doesn’t have that kind of memory. Or here’s another possibility—he gets