He had paused and had placed the receivers to his ears. By his expression I knew that the instrument was registering something.
"Someone is in the lower room of the shop next door," he answered, facing us quickly. "If we hurry, we'll have him cornered."
Miss Laidlaw and I went out and around in front, while Craig dashed through a back door to cut off retreat that way.
"What's that? Hurry!" exclaimed Miss Laidlaw.
Plainly there was a muffled scream of a woman as we entered the street door. I hurried forward. It was the work of only a few seconds to batter down the locked door in the room under Creighton's old workshop, and as the door gave way, I heard the sound of shattered glass from the rear which told that Kennedy had heard the scream, too, and had gained an entrance.
Inside I could make out in the half-light a man and a woman. The woman was running toward me, as if for help.
"He got me here--to kill me!" she cried hysterically. "I am the only one who knows the truth--it was the last day--tonight he would have had the money--and I would have been out of the way. But I'll expose him--I'll ruin him. See--he came in from the roof--"
A blinding flash of light greeted us, followed by a scream from Adele Laidlaw, as she ran past us and dropped on her knees beside a body that had fallen with a thud in the flame before a yawning hole in the side wall.
Mrs. Barry ran past me, back again, at almost the same moment. It was a strange sight--these two women glaring at each other over the prostrate figure of the man.
"Here's the real demon engine," panted Craig, coming up from the back and pointing to an electric motor as well as other apparatus consisting of several series of coils. "The perpetual motion machine was just a fake. It was merely a cover to an attempt to break into the bank vaults by electrolysis of the steel and concrete. Creighton was a dummy, a fiction--to take the blame and disappear when the robbery was discovered."
"Creighton," I repeated, looking at the man on the floor, "a dummy?"
"Oh--he's dead!" wailed Adele Laidlaw. "He's dead!"
"Electrocuted by his own machine rather than face disgrace and disbarment," cut in Craig. "No wonder she was in doubt which of the two men fascinated her most."