‘Right.’ Sachs looked over her detailed chain-of-custody card, which noted the exact location of each sample.

‘Hm.’ He grunted.

‘What, Linc?’ Sellitto asked.

‘Those’re materials used in welding. Oxy-fuel welding primarily. Maybe it came from our unsub but I’d think it’s more likely from the workers who installed the pipe. But we’ll put it on the chart anyway.’

Cooper selected another sample. It was from the floor near the ladder that led to the manhole. When this analysis was finished the tech frowned. ‘Well, may have something here.’

Rhyme sighed. Then share it, please and thank you, his burdened smile said.

But Cooper wasn’t going to be rushed. He carefully read the mass spectrum – the computer analysis from the instruments.

‘It’s tetrodotoxin.’

Rhyme was intrigued. ‘Ah, yes, we do have something here. Another possible murder weapon.’

‘Poison, Linc?’ Sellitto asked.

Mel Cooper said, ‘Oh, indeed. A good one. It’s from the ovaries of the puffer fish, the fugu. It’s a neurotoxin with no known antidote. Sixty or so people a year die in Japan – from eating it intentionally. In low dosages you can get a high … and survive to pay the check. And for what it’s worth, tetrodotoxin’s the zombie drug.’

‘The what?’ Sellitto asked, barking a laugh.

‘Really.’ Cooper added, ‘Like out of a movie. In the Caribbean people take it to lower their heart rate and respiration to the point where they appear dead. Then they come back to life. Either for religious rituals or as scams. Anthropologists think it might’ve been the source for the zombie myth.’

‘Just the diversion for a slow Saturday night in Haiti,’ Rhyme muttered. ‘Could we stay on point here? On focus? On message?’

Cooper pushed his glasses higher up on his nose. ‘Very small trace amounts.’

‘Unless the ME finds some in Chloe’s blood, he’s probably planning to use it for a future attack.’ Rhyme grimaced. ‘And where the hell did he get it? Probably caught a puffer fish himself. Like he grew the hemlock. Keep going, Mel.’

Cooper was reading from Sachs’s chain-of-custody card. ‘Here’s something from a footprint – one of his, I’m assuming, since it was near the ladder. And obscured.’

Booties …

‘That’s right,’ Sachs confirmed. Cooper showed her the mass spectrum and she nodded, then transcribed the computer analysis to the whiteboard.

• Stercobilin, urea 9.3 g/L, chloride 1.87 g/L, sodium 1.17 g/L, potassium 0.750 g/L, creatinine 0.670 g/L

‘Crap,’ Rhyme muttered.

‘What’s wrong?’ Pulaski asked.

‘No,’ Rhyme replied. ‘Literally. Fecal material. Why that? Why there? Any deductions, boys and girls?’

‘There were DS – Sanitation – pipes overhead, but I couldn’t see any sewage on the ground or walls. Probably didn’t come from there.’

‘Dog-walking park?’ Sellitto suggested. ‘Or he owns a dog.’