"And don't worry about all this business," he went on, jerking his head towards the court. "I'll look after your interests here. Just send a wire to the house if you're coming back to town to-night."

I nodded—I think my face showed my thanks—and in another moment we had hurried down the corridor and were outside the building.

In the roadway stood a powerful Rolls-Royce with an embarrassed-looking chauffeur at the wheel. It was already surrounded by a crowd of spectators, while the stream of people coming out from the main entrance was adding momentarily to the congestion.

Billy elbowed his way through with scant ceremony and opened the door of the car.

"You come in with me, Jack," he said. "Wilton will go in front."

The next minute we had glided down the street and twisted noiselessly round the corner into the roar and traffic of the Strand.

Billy didn't wait for me to question him. "It was this way, Jack," he said quietly. "I went round this morning to fetch Mercia at half-past ten as I'd arranged yesterday. When I rang the bell and asked for her, the servant said she'd gone out directly after breakfast. Well, I didn't worry much: I thought that perhaps she'd had some shopping or something to do first, and that she'd be coming back in a minute or two, so I said I'd call again in a quarter of an hour. I was just turning away when a taxi ran up alongside of me, and who should jump out but our friend Wilton here. I knew who he was—I'd met him at Gordon's yesterday—and I could see at once from his face that something was devilish wrong. The first thing he asked me was whether Mercia had come back. When I said no, he looked more worried than ever, and in about two minutes I'd made him choke up the whole story.

"It seems Mercia had come out of the house about half-past nine. Wilton, who'd been told by Gordon not to lose track of her on any account, followed her as far as Sangatte's house in Belgrave Square. She reached there at a quarter to ten, and he'd hung about outside for the best part of half an hour. Then suddenly Sangatte's motor rolled up to the door, and Sangatte himself came out with Mercia and got inside. Of course there wasn't a taxi handy, and before Wilton could find one the car was out of sight. It struck him as just possible that Sangatte might merely be seeing Mercia home, so he'd come along back to find out."

Billy paused for a moment as the Rolls-Royce, dexterously steered by its driver, wormed its way across the crowded Mansion House Corner. With my heart full of anxiety and torn with a murderous anger, I waited for him to continue.

"I guessed something of what had happened," he went on as the car turned off down Aldgate. "I knew Mercia had heard Sangatte mentioned in court as being one of the principal witnesses for the police, and it struck me at once that he'd probably used this fact to get her to come and see him. Nothing but the idea of helping you would have taken her to his house—I felt sure of that. The thing to find out, of course, was what particular dirty game he was trying to play. I chewed it over for a minute, and then it seemed to me that the best thing to do was to go to his house and see when he was expected back. Wilton agreed with me, so we jumped into the cab and ran down to Belgrave Square. His butler answered the door,—a white-faced, cunning-looking sort of skunk,—and when I asked for Sangatte, he said he was out of town. He wouldn't tell me any more at first—declared that he 'didn't know where his lordship was or which day he intended to return'; and when I pressed him a bit, he was half inclined to be cheeky. I saw the only way was to bribe him. He looked like the sort of man who'd sell his mother, so I told him straight out it would be worth a tenner to him if I could find Sangatte before the evening. With that he started to bargain. I suppose he guessed that it was Mercia I was after, and that I couldn't afford to break his neck—anyway, he stuck out for a pony, and of course I had to give it him. Then I got the truth—at least, I think so. Sangatte, he said, had gone off yachting for three or four days, and my only possible chance of catching him was at Burnham-on-Crouch, where his boat was lying."