The two figures in front of Fay’s automatic hesitated, spread, and bolted to right and left. Fay lowered his gun, fired once at the ground, then dashed in pursuit of the taxi-driver, whose khaki leggings were a fair mark to follow. He gained with each stride. He reached forward, stumbled over a low wall, and clutched a coat which was torn from his fingers. He bounded across a roadway, dropped the automatic and made a flying tackle which brought his quarry to the close-cropped grass. “Lie still, you!” he ordered as his fingers closed on a pair of flailing arms. “Get down! I think I know you!” * * * * * Fay’s hands gripped with strength. He heard a low moan below him, and eased the clutch he had fastened upon a thick throat. He wheeled and stared toward the courtyard. Rake had already secured his prisoner. The big ex-convict was looking up the road, which merged into gloom and dripping trees. A man was bounding along this road, with Yeader close behind him. The Cockney raised his revolver in a slow aim. He lowered it and dashed on. A taxi with blazing cones of yellow light swung over the bridge across the railroad track and began descending the grade. It slowed. It stopped with a shriek of metal bands on metal. Two drivers sprang from the front seat and reached for the man whom Yeader was pursuing. He sank to his knees in the roadway as other forms scrambled from the taxi. He was surrounded by a resolute group of taxi-drivers. Their leader called an order and came running toward the taxi in the courtyard. Fay twisted his fingers in a close collar, ran his hand over the figure below him and found, in a pocket, a matted red wig. He sprang erect. “The mechanic of the garage!” he exclaimed. “You settle one doubt! You impersonated Elsie De Groot!” The leader of the drivers who had arrived in the second taxi ran across the courtyard, paused, and stared at Fay’s prisoner. She turned with her eyes sweeping the windows of the silent house. She came over the grass. “Just in time, Miss Elsie!” said Fay. “You got a man up the road. Who was he?” “A crook! And this is--” “This is one of your mechanics. He resembles you. He must have had access to your desk. He impersonated you by putting on a wig after you set Stephney down on Fifth Avenue. He was Ponsardin’s tool. His taxi was equipped with a suction pipe and a set of snap locks on the doors. It was death to enter it. They were after big game tonight.” The girl shuddered. She turned away from Fay and his prisoner. “I don’t know how it all happened,” she said. “I suspected the mechanic after your visit. We followed him tonight. He had a taxi exactly like ours. We lost him in the Park. We were close behind you. Then--we found the trail again, up above Yonkers. It led here. You see, he had different tires than most cars. One was vulcanized on the tread and made a different mark in the dust.” “That was clever!” The girl trembled slightly.