She explained, ‘It was sitting by itself about ten feet from Samantha’s body. It just felt wrong being there. I looked at it closely and saw a needle sticking up. Very small. I used forceps to collect the bag.’ Sachs added that she’d been on the lookout for traps because the NYPD psychologist, Terry Dobyns, had told them the perp might start targeting his pursuers.

‘That’s sneaky,’ Cooper said, donning an eye loupe to examine the needle. ‘Hypodermic. I’d say thirty-gauge. Very small. White substance inside.’

Rhyme wheeled close and looked; his keen eyes could make out a tiny glint near the clasp.

Cooper selected a hemostat and then cautiously lifted the purse from the bag.

‘Check for explosives,’ Rhyme said. This wasn’t the unsub’s MO but you could never be too careful.

The scan came back negative. Still, Cooper decided to put the purse in a containment vessel and used remote arms to open the bag, given the possibility that it was also rigged with some trap that might spray with toxin whoever opened it.

But, no, the needle was the only trap. The contents were mundane, if wrenching, clues to a life now abruptly ended: a health club membership card, a breast cancer donation thank-you note, a discount certificate to a Midtown restaurant. Pictures of children – nieces and nephews, it seemed.

As for the booby trap, Cooper extracted the needle carefully.

‘It’s small,’ Rhyme said. ‘What do we make of that?’

Cooper said, ‘Can be used for insulin but this type is mostly used by plastic surgeons.’

Rhyme reminded, ‘He’s got propofol too. A general anesthetic. Could be that he’s planning some cosmetic surgery as part of his escape plan. Though maybe he just broke into a medical supply house and stole what he wanted. Sachs, check if there’ve been any reports of that in the past month or so in the area.’ She stepped away to make a call downtown, requesting an NCIC search. Rhyme continued, ‘But more to the point – excuse the expression – that needle in particular: What’s inside his little present to us? Is it more of the angel’s trumpet?’

Cooper ran the sample. And a moment later he read the results. ‘Nope. It’s worse. Well, I shouldn’t say worse. That’s a qualitative judgment. I’ll just say it’s more efficient.’

‘Meaning deadlier?’ Rhyme asked.

‘A lot. Strychnine.’ Cooper explained: The toxin came from Strychnos, a genus of trees and climbing shrubs. The substance was popular as a rodenticide. It had been a common murder weapon a century ago though it was less so now since it was easily traced. Strychnine was the most pain-inducing of any toxin.

‘Not enough to kill an adult,’ Cooper said. ‘But it would keep the victim out of commission for weeks and might cause brain damage.’