"Who came out of the building after that?"

"Quite a number of people, sir. Going out for supper-parties and so on. I recognised most of them as residents."

"And that you did not recognise?"

"There was a woman. Looked like a working woman, I thought, and a couple of housemaids, and before them an old gentleman in a soft hat and a dinner suit and a sort of opera cloak. He was a bit lame. The commissionaire got him a taxi. I heard him say 'The Platza Theatre' to the driver. I asked the commissionaire about them just to be on the safe side. He's a dense sort of bloke. He thought the woman must have been doing odd work in one of the flats. The old gent he didn't know, but said he came from the top floor, and had probably been dining there. The housemaids came from the street-level flat."

"That's all?"

"No, sir. One other. A young fellow wearing a shepherd's plaid double-breasted suit, a bowler hat, and a dark blue tie with pale blue stripes, came along. I crossed the street and heard him name our party's floor to the liftman."

"Had he a fair moustache and a carnation in his coat?"

"Yes, sir."

"Did he reappear?" Alleyn asked sharply.

"He came out again after about five minutes and walked off towards the square. That's all, sir. I was relieved at ten-fifteen by Detective-Sergeant Allison. He's still on duty."

"Thank you. That's all, Watkins."

"Have I gone wrong anywhere, sir?"

"Yes. You've mistaken a murderer for an innocent person. I don't know that I blame you. Get one of these men to relieve Allison and ask him to report here immediately."

Watkins said nothing, but looked miserable. He and Thompson conferred sympathetically. After a few moments Watkins said diffidently:

"If I may, sir, I'd like to relieve Allison myself."

"Very well, Watkins. If anybody comes away from the building, man or woman, stop them, speak to them, get their names and addresses and make sure they are what they seem. Thompson, you can go too if you like. Don't look so injured, both of you. We've all gone wrong over this."

A pause, and then Thompson addressed the lining of his hat with some feeling.

"We'd both go back on P.C. night-duty before we'd let you down, if you know what I mean, sir."

"That's right," said Watkins fervently.

"Well, push off, you couple of boobies," said Alleyn. He turned to Fox. "I'm going to the telephone. The statement from Peterhouse ought to be here any moment. If Allison comes before I'm back, get a report on those lines from him."

"Are you going for a warrant-to-arrest tonight?" asked Fox.

"I don't think so. I'll still stage my performance tomorrow morning."