But as I stood up, the police car had already come off the tarmacadam and was crunching over the gravel toward the dock. Two men got out, both of them plainclothes detectives, wearing macks and trilby hats in the time-honored tradition. I didn’t recognize either of them—not that I’ve had much to do with local police. I was about to say, “Can I help you?” when one of them called out, “We’re looking for Count Paolo di Martini. Either of you girls know if he’s around here?”

My hackles rose a trifle at being addressed as “you girls.”

“You’ll find him out in that blue boat,” I said coldly.

“What do you want him for?” Belinda asked, but they walked past her as if she didn’t exist. Out at the end of the dock they shouted Paolo’s name and gestured that he should come to shore.

“Go away,” Paolo called. “Can’t you see that I’m busy?”

“Detective Inspector Manson, Metropolitan Police,” one of them shouted, and held up his warrant card. “We’d like to speak to you immediately, if you don’t mind, sir.”

“I do mind,” Paolo said.

“Then let me rephrase it. Signor di Martini, we would like you to help us with our inquiries.”

“Go to hell,” Paolo said.

“In which case you leave me no alternative. Paolo di Martini, you are under arrest.”

“What? What are you talking about?”

I don’t know how long the shouting might have gone on if Ronny hadn’t got the motor started and brought the boat to the dock.

“What nonsense is this?” Paolo demanded as he scrambled ashore.

“Paolo di Martini, I arrest you in the name of the law for the manslaughter of Mavis Pugh.”

Paolo looked almost amused. “Who in God’s name is Mavis Pugh? I have never heard of her.”

Ronny gave a little cry and leaped ashore after him. “It was you, Paolo. You ran her down. You horrid, callous beast. How could you do such a thing?” She flung herself at him as if she was about to strike him.

Paolo put up his arms to defend himself. “But I do not know this person.” He looked bewildered and scared now. “What is this? I am innocent. Belinda, tell them I am innocent. You say I have killed someone? Is not possible.”

“You own a motorcycle, do you not? A motorcycle that we found in your hangar at Croydon Aerodrome?”

“Yes, but . . .”

“On that motorcycle we found conclusive evidence linking you to the hit-and-run death of a young woman. We found traces of her hair and fiber from her jacket on your tires and frame. Now I should warn you that you have the right to remain silent, and anything you say can be used as evidence against you. So if you’ll just come with us without a fuss.” He put a big hand on Paolo’s arm.