Thank you, Sachs thought, following in the creature’s general direction – toward the distant end of the tunnel. If the rodent was walking so nonchalantly over the ground it was unlikely that an ambush awaited. She continued walking. In sixty or so yards she came to the bricked-up wall. There were no footprints here – normal or bootied – so their perp hadn’t wandered this way. She returned to the ladder.

She lifted out her cell phone – encased in uncontaminating plastic – and called up the GPS map. She noted that she was underneath Elizabeth Street, to the east, near a curb.

Sachs turned up the volume to the headset.

‘I’m below the manhole, Rhyme.’ She explained where it was and that this was likely how he’d gotten in, because there was significant moisture on the ground; the manhole cover had probably been removed in the past hour or so, she estimated. ‘It’s muddy here.’ A sigh. ‘But there’re no prints. Naturally. Let’s have Lon canvass the stores and apartments around the neighborhood, see if anybody saw the perp.’

‘I’ll call him. And get any security CCTVs too.’ Rhyme was skeptical about witnesses. He believed that in most cases they were more trouble than they were worth. They misobserved, they had bad memories – intentionally and otherwise – and they were afraid to get involved. A digital image was far more trustworthy. This was not necessarily Sachs’s opinion.

She swabbed the rungs as she climbed the ladder, depositing the adhesive cloth in plastic evidence collection bags.

At the top she rolled the underside of the manhole cover, then lifted a small alternative light source unit to check for fingerprints on the surface. ALS’s are lamps that use colors of the spectrum of visible light (like blue or green) combined with filters to make apparent evidence that’s impossible to see under regular bulbs or in daylight. ALS sources also include invisible light, like ultraviolet, which makes certain substances glow.

The scan, of course, revealed no prints or other evidence from their unsub. She tested the manhole cover’s weight; she could budge it but just barely. She supposed it weighed close to a hundred pounds. Hard to push open but not impossible for a strong individual.

She heard traffic overhead, the shushhh sound of tires cutting through the wet sleet. She was shining the light straight up, looking into the hole through which a worker would feed the hook to remove the cover. Wondering about marks that might lead them to a particular brand of tool the perp had used. Nothing.

It was then that an eye appeared through the hole.

Jesus … Sachs gasped.