We walked back over rails and through trash alive with rats. I sensed Commander Penn was crying. Minutes passed.

She said, ‘Davila was a good officer. He was so helpful, never complained, and his smile. He brightened a room.’ Her voice was clenched in fury now. ‘He was just a goddam kid.’

Her officers were around us but not too close, and as I looked down the tunnel and across the tracks, I thought of the subterranean acres of twists and turns of the subway system. The homeless had no flashlights, and I did not understand how they could see. We passed another squalid camp where a white man who looked vaguely familiar sat up smoking crack from a piece of car antenna as if there were no such thing as law and order in the land. When I noticed his baseball cap the meaning didn’t register at first. Then I stared.

‘Benny, Benny, Benny. Shame on you,’ one of the officers impatiently said. ‘Come on. You know you can’t do this, man. How many times are we going to go through this, man?’

Benny had chased me into the medical examiner’s office yesterday morning. I recognized his filthy army pants, cowboy boots and blue jean jacket.

‘Then just go on and lock me up,’ he said, lighting his rock again.

‘Oh yeah, your ass is gonna be locked up, all right. I’ve had it with you.’

I quietly said to Commander Penn, ‘His cap.’

It was a dark blue or black Atlanta Braves cap.

‘Hold on,’ she told her troops. She asked Benny, ‘Where did you get your cap?’

‘I don’t know nothing,’ he said, snatching it off a tuft of dirty gray hair. His nose looked as if something had chewed on it.

‘Of course you do know,’ the commander said.

He stared crazily at her.

‘Benny, where did you get your cap?’ she asked again.

Two officers lifted him up and cuffed him. Beneath a blanket were paperback books, magazines, butane lighters, small Ziploc bags. There were several energy bars, packages of sugarless gum, a tin whistle and a box of saxophone reeds. I looked at Commander Penn, and she met my eyes.

‘Gather up everything,’ she told her troops.

‘You can’t take my place.’ Benny struggled against his captors. ‘You can’t take my motherfucking place.’ He stomped his feet. ‘You goddam son of a bitch …’

‘You’re just making this harder, Benny.’ They tightened his cuffs, a cop on each arm.

‘Don’t touch anything without gloves,’ Commander Penn ordered.

‘Don’t worry.’