AARON TOYED WITH THE idea of letting Wildsmith know about Paul immediately, and decided against it. Going to see him risked looking eager in some way he didn’t care to define, especially since he might be coming back if Hollis found a possible case to use as trial. Anyway, if Wildsmith had to worry a little longer, it would do him no harm and might cause him to reflect on the wisdom of making actionable claims about strangers.

He went back to work the next day, and was instantly presented with a case that drove the graphologist from his thoughts.

“Body in the canal,” he told Challice. She was looking rather drawn after yet another complaint of rape that had gone nowhere. He hated sexual offence cases: the shame and distress of the victims, the ugliness of the questions that had to be asked, and the frustrating difficulty of getting a conviction, still less a sentence that reflected the harm done.

DI Davis always put Challice on those cases. Aaron wondered if he realised how cruel that was. On darker days, he wondered if Davis knew it very well.

She deserved a bit of fresh air, he felt, which in this instance meant a corpse fished out of the Regent’s Canal. “Chap’s got a head wound so it needs looking into. Want to come with me?”

She beamed as though he’d asked her to dance. “I’d love to.”

The body was one Gerald Marks, going by a battered card-case in his pocket and a laundry mark. He was middle-aged, and looked decidedly shop-soiled, although a night in the Thames would do that to you. His coat had also seen better days, but he had a very nice gold watch in his fob pocket.

“Which is still there,” Aaron pointed out. “Wallet gone, watch left. If it was a robbery, it wasn’t an efficient one.”

The head wound was nasty, fracturing the back of the skull. “Could be a bludgeon, could be a paving stone. It was raining last night, so he could have slipped, and cracked his head. Not clear how he got into the canal, if that was the case.”

The sodden body lay on the towpath. They were both crouching by it in the mud, damply dusted by the relentless drizzle. The glamour of policing. Aaron looked around. “Maybe he tried to get up and fell in? I’ve seen people keep moving with worse injuries than this.”

“But his wallet has gone, all the same,” Challice said. “So, a robbery—or an accident, and a passer-by helped themselves to the wallet and shoved the body in?”

“Possible. Where was he found?” Aaron asked the uniformed constable who was hanging around, huddled under his rain-cape.

“Just where he lies, sir, only in the water. Close by the edge. A few of the boatmen fished him out with a hook.”