Seawoll had been waiting for us in the tent. He grunted when Lesley led us in. ‘Somebody’s just taking the piss now.’

‘It’s escalating,’ I said.

Nightingale gave me a sharp look but said nothing.

‘But what’s escalating?’ asked Lesley. ‘And why can’t you stop it?’

‘Because, Constable,’ said Nightingale coldly. ‘We don’t know what it is.’

There were plenty of witnesses and suspects, and people who were helping the police with their inquiries. We paired off to conduct the interviews as fast as possible. I worked with Seawoll while Nightingale paired with Lesley. That way there’d be someone in the room who could spot a vestigium when it slapped him in the face. Sergeant Stephanopoulos handled the collecting of physical evidence and collating the CCTV coverage.

It was a bit of a privilege to watch Seawoll work. He wasn’t nearly so intimidating with the suspects as he was with other policemen. His interrogation technique was gentle – never chummy, always formal but he never raised his voice. I took notes.

The sequence of events, as we reconstructed them, was depressingly familiar but on a larger scale than we’d seen before. It had been a mild spring Sunday afternoon, and St Martin’s Court had been moderately crowded. The Close itself is a pedestrianised alleyway that has access to three separate stage doors, the back entrance to Brown’s and the famous J. Sheekey’s Oyster Bar. It’s where the theatre staff go for a coffee and a crafty fag between performances. J. Sheekey’s is a thespian landmark, which isn’t surprising if you sell food late at night within walking distance of the most famous theatres in the West End. Sheekey’s also employs uniformed doormen in top hats and black frock coats, and that’s where the trouble started that afternoon.