"Billy!" I interrupted, rather desperately. "Do you mean that Mercia is alone on board with that brute?"
Billy laid his hand on my arm. "They're only two hours ahead of us, Jack," he said, "and it takes some time to get a boat of any size under way."
"But what does it all mean?" I broke out. "What devil's trick can he have played to get Mercia to Burnham? She knows—"
"It's my belief," interrupted Billy, "that she had no idea the car was going there. Suppose he got her round to the house on the pretence of giving evidence about you, and then offered to drive her down to the court. It's only an idea, of course, but it's in keeping with what one knows about Sangatte, and it fits in with the facts. Once in the car, it would be impossible for her to escape until they got to Burnham; and what could a girl do then against two or three men? No doubt Sangatte's certain of his own crew."
With a bitter oath, I brought down my clenched fist on the side of the car.
"If you're right, Billy," I said slowly, "I'll make Sangatte sorry he was born."
There was a short silence, as the car swung on through the dreary purlieus of Stratford at a pace which brought belated shouts and curses from the carmen and hawkers that we left behind.
"Go on, Billy," I said, staring out in front of us. "Talk to me, for God's sake, or I shall go mad. Tell me how you got hold of the car."
"Hired it," said Billy. "I saw at once that if this butler skunk was speaking the truth, the only thing to do was to make a run for Burnham. I thought of your car at first; then it struck me there might be a bit of a bother getting hold of it, so I drove straight down to Garrett's in Bond Street and ordered a Rolls-Royce. They took about ten minutes getting it ready, and while they were messing about I sent Wilton round in the taxi to make certain Mercia hadn't gone home. Then we came right along to Bow Street to let you know how things stood before we started for Burnham."
He paused and, bending down, lighted a cigarette.