“Why?”

“Less chance of you being tried for assault.”

Hammell’s eyes narrowed still further. “Maybe you should just spit it out.”

Rebus considered his options. “Okay then,” he said, leaning in towards the open window and lowering his voice. “Is Annette McKie your daughter?”

The car door swung out suddenly, catching Rebus a glancing blow as he backed away. By the time Hammell got out, Rebus had put some distance between them. They stood in the middle of the road, twelve feet apart.

“Hell are you saying?” Hammell snarled.

“Sure you want to do this here, Frank?” Rebus indicated the dozens of tenement windows either side of them.

“She’s fifteen years old,” Hammell went on, taking a couple of steps towards Rebus, fists bunched. “You saying I was doing her mum behind Derek’s back?”

“I’m saying you’re acting like a parent—tailing her, keeping tabs on her, giving her money, and then having fights about how she spends it and who she sees. And if that’s not the case…”

“Which it’s not,” Hammell spat.

“Then there’s another scenario we need to discount.”

“And what’s that?” Hammell’s eyes were huge and he was breathing heavily, as if pumping himself up for combat.

“There’s forensic evidence, Frank. A pubic hair that doesn’t belong to Annette. Once the lab get a DNA profile, they’re going to match it against her sexual history. They want to know if it belongs to whoever killed her, or just someone she’d been seeing.”

Rebus had backed away a couple of steps, but Hammell was no longer moving.

“So I have to ask, Frank—were you and Annette an item? Because if you were, then there’s a good chance of that DNA coming straight back to you. And meantime the team will have been tied up on a wild goose chase, giving the real killer more time to cover his tracks.”

“You’re asking if I was sleeping with my girlfriend’s daughter?”

Rebus didn’t say anything.

“Is that what you’re asking?” Hammell persisted. When Rebus stayed silent, he launched himself forward, his whole weight landing on Rebus, both men hitting the ground. Rebus felt all the air being punched out of his body. Hammell was trying to gain some purchase, Rebus rolling so he could dislodge his attacker. A delivery van had entered the street but stopped dead, its driver emerging to watch. Rebus gave Hammell a shove and started getting to his feet, but Hammell’s foot caught him in the ribs and he went down again, grazing his knuckles against the tarmac.

“You piece of—”

Hammell didn’t get the chance to finish the sentence. His groin was just the right height for a headbutt, and that was what Rebus delivered. Hammell gasped and pitched forward, Rebus grabbing him by the hair and pulling him down until his face met the road surface. The van driver had made tentative progress towards the two men.

“You need to break it up!” he cautioned. “Somebody’s going to be calling the police!”

Rebus was on his feet, heart racing, head pounding from where it had made contact with the ground. When he inhaled, his ribs complained. Hammell was on hands and knees, spitting dribbles of blood from his mouth. Rebus made sure there was distance between them and waited for the man to get up. Hammell’s face was almost purple, bits of grit stuck to it.