We struck pay dirt on the fourth alley. There was a dumpster there, filled with the usual trash and garbage. We grabbed an old fence board and snaked around in the mess awhile before we turned up a shopping bag with a canvas strap sticking out of it. I reached down and plucked out the bag by a corner. Inside were two army-issue gas masks. Canvas and rubber, brand-new, each in a little canvas carrying pouch. I kept rummaging with the fence board, turning over juice and booze bottles, beer cans, frozen-dinner trays, plastic garbage bags, and junk. Then I saw it.
"Look. There's your bomb, Joe."
"That can? Hey yeah. Look, Kev, it's all burnt. I see a horse on the side of it. A horse jumping over a fence."
"It's a tobacco can," I said. "Kentucky Club. A tobacco can with a pry-off top is perfect; don't you see? The lid's a friction fit, and airtight."
I drew out the scorched can carefully, holding it by the lip. It was a few minutes before we located the burnt and blown-out lid with the little metal sliding pry lever still attached. We looked at the can. A household electrical cord ran from its side right near the bottom edge. The hole had been made neatly; it was just the right size. Putty had been packed in around the cord. On the can's interior bottom the broken copper strands of the wire were fused solidly, and all around the wire ends was a white powdery ashlike deposit.
"Take that goddamn thing away from your nose, Doc, you'll croak!" yelled O'Hearn. I thanked him for reminding me.
"Wire's melted all over in here," I said. "It took a terrific amount of heat to do that. I'd say they used powdered magnesium, or flash powder. Maybe they mixed in some crude gunpowder too, for more oomph. This stuff here would be magnesium oxide."
"How come you know all about that chemistry stuff?" asked O'Hearn belligerently. "Thought you were a doctor."
"A lot of medicine is chemistry. In my work with teeth I deal a lot with metals and alloys… and their oxide residues come with the territory I guess."
The cord was long, about twenty feet, and terminated in a standard-issue plug. They'd used current from Robinson's apartment to set off the lethal bomb. Seven feet from the plug, the wire on one side of the cord was stripped and cut. The wire on the other side remained whole.
"See? Here's their crude knife switch," Joe said. Then, holding the wire ends about a half-inch apart by the insulation still cleft on the cord, he touched them together several times.
"This opens and closes the circuit just like a switch in the cord. Now the ends of the wires in the can were joined to a fuse wire- a thin wire that'd heat up really fast as soon as house current was run through it. Then this wire is covered with an explosive substance, like flash powder."
"Yeah, a rocket fuse," said O'Hearn. "But how 'bout the gas? Where does it come from?"
"Don't know. There's lots of different kinds. Phosgene- that was the favorite of the Third Reich. Cyanide is probably the most widely used. That's what they use in prison gas chambers? "Then aren't there special military gases? Nerve gas? Paralyzing gas? Stuff like that?"
"Yeah. But if it was homemade, which it appears to be, then cyanide is the best bet. All you need, if I remember right, is ferrocyanide crystals and sulfuric acid. You can get those chemicals. It's hard but it can be done. Then when they're mixed- bingo, poison gas. Sometimes it goes by the name prussic acid. Same deal though. Instant death. Let's take this stuff back to the house for a mock-up."
The lab boys were all over the place. They had Robinson and his two dogs covered and placed on litters in the living room. The print guys were dusting windowpanes, doorknobs, chrome table legseverything that would take a print. They blew powder all over the place, swept big soft brushes over surfaces, lifted prints off with special Scotch tape. It was absorbing to watch them, like watching bricklayers or blacksmiths.
One guy was working on the wallpaper that had been scorched in the hallway. He was delighted when we handed him the empty and burnt-out Kentucky Club can. When the can was placed against the wall under the small table the scorch mark began right above its lip and fanned out and upward. You could almost visualize the big flash the explosion had made, probably blowing the metal lid up against the table. The cord ran back under the carpet runner, under the bedroom door, and into the wall socket with some to spare. Enough cord was left for a person to stand behind the door staring through the peephole with the pieces of cut cord in his hands. When he sees Robinson come up the hall, he touches the wires together. Boom! Poison gas in the hall. Robinson falls, dogs charge the door in a death agony. We acted it all out. The pieces fit.
The lab man fiddled with bottled solutions and test paper. He took scrapings from the can and the wallpaper.
"Potassium-cyanide," he said softly as he watched the solutions change color. "Or prussic acid; take your pick of names. Lethal within seconds."
"What do you think, Larry? Pro job?"
The man nodded and left, taking the evidence with him. We sat at the kitchen table now that the crew was through dusting. My brother-in-law sighed.
"Nice going with the can and stuff, Doc. Gotta hand it to you. Well, the big boys got Johnny at last. A simple gas bomb, made with everyday things impossible to trace, but deadly, and built with a lot of experience. Poor guy. And I guess you're out of luck as far as the dental piece goes too."
"Good God, Joe! Mary! She's been in the Lucky Seven all this time. Do you think-"'
We hustled downstairs and around the corner. There was I quite a crowd around the bar now. It was getting on toward evening. Mary was nowhere to be seen. We asked the barkeep and he nodded in the direction of a crowded table.
The men around the table were huddle-tight. They were yelling encouragement at invisible parties. We approached and saw two arm wrestlers at the table. One was a wiry guy about my age with rolled-up sleeves and tattoos. His arms were stringy and pretty thick. He looked strong. The other combatant was Mary. She seemed to be winning.
The crowd's chatter increased. Money was changing hands. Mary's face contorted with effort and pain as she pushed to put the man down.
"Come on, Mare!" shouted Joe.
"Hey, you know that broad?" asked a bystander. "Man, is she strong!"
"And mean," I added.
"Yeah?"
There were three more shot glasses near her left hand, all empty. But then I saw a bottle snake in and out, and one of the glasses was full. Mary reached for it with her free hand and knocked it back. Now where the hell did she learn that? As her head went back she saw my face and slammed the glass down.
"Hi good-lookin'!" she called. And lost the match.
Her opponent, sensing her lack of concentration, made a final assault and slammed her hand down on the table. Some of the crowd booed, but I couldn't tell if it was directed at the opponent who took advantage or at Mary's defeat. A half-dozen guys were headed for the bar to buy Mary some more liquid candy cane; I stepped in and snagged her.
"That's the nicest place!" she exclaimed as she tripped along the cracked sidewalk between us. We helped her negotiate it now and then.
"Those guys were just trying to get you drunk, Mare. They weren't being nice," said Joe.
"Right," I said. "They were just trying to get you drunk so they could get in your pants, right Joe?"
"Absolutely."
Mary stopped and weaved. She stared at us, squinting in incredulity.
"Really? Really, you guys? They wanted to get in my pants?"
"Yep," I said. "That's all they wanted. They just- hey!"
She was heading back toward the bar. She wasn't dawdling either. We caught her and turned her around.