When he arrives at the scene, Enfield is waiting for him and holds out a palm for a bone-crushing handshake. An awkwardness between them now. Because there had been the start of something and then Oscar arrived and now they’re . . . what exactly? Regardless, something has changed.

The building is still surprisingly intact, the only difference from yesterday a couple of smashed windows and a little charring to the bricks above them. The fire is already out.

“I can’t let you go in,” Enfield tells him. “The structure’s not sound. We’ll need to shore up the properties on either side.”

Tyler eyes the little brass plaque by the door. Denham, Carter & Carter. No doubt now that the fires are somehow related to the Cartwright case. “Was anyone hurt?”

Enfield shakes his head.

He points to the plaque. “Is this why you called me?”

Enfield looks at the name and shakes his head. “No. I called because there are similarities between this and the other fires. Petrol again, though we’ll have to do tests to make sure it’s the same type. But also, there’s the same sense of control.” He doesn’t sound sure, though. He looks up at the building, still frowning. “There are some differences. The fire didn’t take hold; the epicenter was a rubbish bin soaked in petrol, but he didn’t soak the whole place like he has before.”

“Perhaps he ran out.”

“Then there’s the location. We’re a long way from Castledene.” He goes back to his study of the building, and Tyler notices a small vein throbbing on the man’s neck as he concentrates. The vein is bisected by a deep scar, a raised white ridge that begins close to his collarbone and widens as it disappears under his T-shirt. “This feels different. I don’t think the fire was meant to do much damage. It’s more like a message.”

“But you do think it’s the same arsonist?”

Enfield thinks about this. “We’ve seen a dramatic increase in the number of incidental fires over the past week, right across the country. It isn’t that unusual for this time of the year, especially given the weather we’ve been having. But the spike this week has been greater than the statistical norm. We can’t work out why.”

“They can’t all be the work of one man.”

“No, most of them are far less serious. Fires in rubbish bins, bonfires on wasteland, that sort of thing. Kids’ stuff. We’ll invest some time in going round the schools, and hopefully it will settle down before anyone gets seriously hurt.” He frowns again. “This is different. I suppose it’s more of a feeling than anything. A signature you learn to recognize.” Enfield is more than half-talking to himself. “If this is the work of our guy, though, then he’s broken his pattern. That would indicate to me this place wasn’t just a random choice. That means in all likelihood the others weren’t either.”