When it comes to crime scene contaminants, water can be worse than fire. Much trace can survive flames and, while walls may collapse, the position of objects and architectural elements and even human bodies at the scene remains largely unchanged. A flood, though, is like a big mixing bowl, not only diluting and destroying and blending, but also moving items far from their original positions.

Water is, Rhyme had frequently pointed out, the universal solvent.

Emergency Service officers had cleared the scene and gotten the victim to the street level. He was doped up but conscious and his only injuries appeared to be bruises from where the water had slammed him into a wall. The unsub hadn’t had time to start on the mod. The vic was bordering on hypothermia but the medical technicians got him out of his drenched clothing and into thermal blankets.

After extracting him, and clearing the scene, the police retreated while two firemen in full biohazard outfits waded through the torrent to shut the flow off. They took water samples too. Rhyme had been concerned that the unsub might have spilled into the water some toxin that, even if diluted, could injure or kill.

An ESU officer came up to them. ‘Detectives. Captain.’

‘Go ahead,’ Haumann said.

‘It’s draining and the fire department’s hooked up a pumper. But it’s still a flood. Oh, and they’ve done a preliminary test of the water and there’s no biohazard or chemicals, nothing significant, at any rate. So they’re pumping to the sewer drains. Should be pretty clear in about an hour.’

The officer said to Sachs, ‘They said they found something you’ll want to see, Detective. One of the firemen’s bringing it out now.’

‘What?’ she asked.

‘Just a plastic bag. All I know.’

She nodded, not holding out much hope it had anything to do with the case. It might hold a banana peel, a joint, coins for parking meters.

Though there was always the chance it was the perp’s wallet or Social Security card.

Nothing more to do here. Sachs and Sellitto walked to the ambulance. They stepped inside, through the back, closed the door. Braden Alexander was sitting in a blue robe, shivering. The ambulance was heated but the man had just gone for a serious dunking in near-freezing water.

‘How’re you doing?’ Sellitto asked.

His jaw trembling. ‘Cold, hazy from whatever the son of a bitch gave me. They said it’s propofol.’ He stuttered as he spoke. His words were slurred too. ‘And seeing him, what he was wearing, it freaked me out.’

‘Could you describe him?’

‘Not real well. He was about six feet, pretty good shape. White. But he wore this yellow latex mask. Jesus. I freaked. I mean, I totally freaked. I said that, didn’t I? Eyeholes and nose and mouth. That was it.’

Sellitto showed him the Identi-Kit image.

‘Could be. Probably. But the mask, you know.’