‘When we weren’t sure where the hypochlorous acid came from we sent patrolmen to the scenes, remember? To see if there were chlorine distribution systems there.’

‘Right. The boutique in SoHo and the restaurant. They didn’t find any.’

‘Yes, yes, yes, but it’s not the acid I’m thinking of.’ Rhyme wheeled closer to the monitor, studying the images. ‘Look at those pictures you took, Sachs. The spotlights and batteries. Did you set them up?’

‘No, the first responders did.’ She was frowning. ‘I assumed they did. They were there when I arrived. Both scenes.’

‘And the officer who searched the tunnel for chlorine later said he was standing by the spotlights. They were still there. Why?’ He frowned and said to Sachs, ‘Find out who set them up.’

Sachs grabbed her phone and called the Crime Scene Unit in Queens. ‘Joey, it’s Amelia. When your people were running the Unsub Eleven-Five scenes, did you bring halogens to any of them? … No.’ She was nodding. ‘Thanks.’ Disconnected.

‘They never set them up, Rhyme. They weren’t our lights.’ She then called a friend at the fire department and asked the same question. After a brief conversation she disconnected and reported, ‘Uh-uh. They weren’t the FD’s either. And patrol doesn’t carry around spots in their RMPs. Only Emergency Service does and they didn’t respond until later.’

‘And, hell,’ Rhyme snapped, ‘I’ll bet there’re lights in the tunnel under the Belvedere.’

Sachs: ‘That’s what the bombs’re in, right? The batteries.’

Rhyme looked over the images. ‘The batteries look like twelve-volt. You can run halogens on batteries that’re a lot smaller. The rest of the casing’s filled with gunpowder, I’m sure. It’s brilliant. Nobody’d question spotlights and batteries sitting in a crime scene perimeter. Any other mysterious packages’d be reported and examined by the Bomb Squad.’

‘But what’s the target?’ Cooper asked.

The brief silence was broken by Amelia Sachs. ‘My God.’

‘What, Sachs?’

‘IFON.’ She dug what seemed to be a business card out of her purse. And walked fast to the crime scene photos. ‘Hell, I missed it, Rhyme. Missed it completely.’

‘Go on.’

She tapped the screen. ‘Those yellow boxes with IFON printed on the side? They’re Internet cables, owned by International Fiber Optic Networks.’ She held up the card. ‘And the building directly over the Samantha Levine crime scene was IFON’s headquarters. She worked for them. I interviewed the CEO just after she died.’ Sachs then called up the photos of the Chloe Moore scene. ‘There. The same boxes.’

And there was another box visible in the tunnel beneath the parking garage in the Belvedere Apartments.

Sachs said, ‘In the hospital, in Marble Hill, where Harriet Stanton was attacked, I didn’t go underground to look for any tunnels. But I’ll bet there’re IFON routers or whatever they are somewhere.’