WILLIAM WESTCOTT next underwent an examination to the following effect:--I live at No. 10, Simmons-street, Sloane-square, Westminster, and am one of the assistant patrol of Bow-street.--On Wednesday night last, I was sent to the stable in Cato-street, by order of Mr. Birnie. I accompanied Ruthven, Ellis, Smithers, and others to the spot. Ruthven went first, and I followed Smithers. I was behind him in the stable. The moment Ruthven, Ellis, and Smithers had gone up the ladder leading to the loft, I seized a man in the stable below dressed like a butcher. His name I believe was Ings.--When I entered, he rushed out against me: and finding resistance, put his hand to his belt, as if to pull something out of it. I immediately knocked him down by hitting him on the right eye. He was dressed in a long coat beneath his jacket, and had an apron over the whole. This happened before the first pistol was fired, and I was in the act of handcuffing him when I heard a fresh pistol fired in the loft. I had not quite succeeded before Thistlewood came down the ladder, and as he was upon the steps fired a pistol; whether levelled at me or not I cannot say. Seeing me so busily engaged in securing the butcher, he levelled another shot at my head, and at the same time made several cuts at me with a sabre. The pistol went off, and the shot penetrated my hat. I knocked him down with the stick I had in my hand, but he rose and succeeded in making his escape. While I was engaged with Thistlewood, Ings contrived to make his escape also; when Thistlewood was gone, I found that I was wounded in the hand, and that some shot had gone through the flap of my coat. In the mean time both Thistlewood and Ings succeeded in getting away. I pursued Thistlewood, but in vain, and after having followed him through several streets, I returned to the stable. I then went into the loft, and saw the deceased lying dead on the floor. There were several persons present, and the prisoners had been subdued. The Jury asked the witness whether Thistlewood was the first who came down the steps?--There was a complete rush, and I did not particularly observe whether he did or not. Did he come down before the officer Smithers fell?--I did not see the officer fall. You went with the whole body of the officers?--Yes, I did. There were only three officers, I understand, in the loft?--I believe no more. Where were the others?--They were upon the scout. Then I understand that after the three officers mentioned had gone up, Thistlewood came down, and prevented others from ascending the steps? Yes; and he fired down the steps to prevent the ascent of others.