Rebus was looking up at the tenement windows. Ground level was shops; Minto lived above a locksmith’s. There was irony there for those who wanted it.

‘OK, you come up with me, but stay on the landing. Only come in if you hear trouble.’

‘You sure?’

‘I’m only going to speak to the man.’ Rebus touched Holmes’s shoulder. ‘Relax.’

The main door was unlocked. They climbed the winding stairs without speaking. Rebus pushed at the bell and took a deep breath. Minto started to pull the door open, and Rebus shouldered it, propelling Minto and himself into the dimly lit hallway. He slammed the door shut behind him.

Minto was ready for violence until he saw who it was. Then he just snarled and strode back to the living room. It was a tiny room, half kitchenette, with a narrow floor-to-ceiling cupboard Rebus knew held a shower. There was one bedroom, and a toilet with a doll-house sink. They made igloos bigger.

‘Fuck do you want?’ Minto was reaching for a can of lager, high-alcohol. He drained it, standing.

‘A word.’ Rebus looked around the room, casually as it were. But his hands were by his sides, ready.

‘This is unlawful entry.’

‘Keep yapping, I’ll show you unlawful entry.’

Minto’s face creased: not impressed. He was mid-thirties but looked fifteen years older. He’d done most of the major drugs in his time: Billy Whizz, skag, Morningside speed. He was on a meth programme now. On dope, he was a small problem, an irritation; off dope, he was pure radge. He was Mental.

‘Way I hear, you’re fucked anyway,’ he said now.

Rebus took a step closer. ‘That’s right, Mental. So ask yourself: what have I got to lose? If I’m fucked, might as well make it good and.’

Minto held up his hands. ‘Easy, easy. What’s your problem?’

Rebus let his face relax. ‘You’re my problem, Mental. Making a charge against a colleague of mine.’

‘He laid into me.’

Rebus shook his head. ‘I was there, didn’t see a thing. I’d called in with a message for DS Holmes. I stuck around. So if he’d assaulted you, I’d’ve known, wouldn’t I?’

They stood facing one another silently. Then Minto turned and slumped into the room’s only armchair. He looked like he was going to sulk. Rebus bent down and picked something off the floor. It was the city’s tourist accommodation brochure.

‘Going somewhere nice?’ He flicked through the lists of hotels, B&Bs, self-catering. Then he waved the magazine at Minto. ‘If one single place in here gets turned, you’ll be our first stop.’

‘Harassment,’ Minto said, but quietly.

Rebus dropped the brochure. Minto didn’t look so mental now; he looked done in and done down, like life was sporting a horseshoe in one of its boxing gloves. Rebus turned to go. He walked down the hall and was reaching for the door when he heard Minto call his name. The small man was standing at the other end of the hall, only twelve feet away. He had pulled his baggy black T-shirt up to his shoulders. Having shown the front, he turned to give Rebus a view of the back. The lighting was poor – forty-watt bulb in a flyblown shade – but even so Rebus could see. Tattoos, he thought at first. But they were bruises: ribs, sides, kidneys. Self-inflicted? It was possible. It was always possible. Minto dropped the shirt and stared hard at Rebus, not blinking. Rebus let himself out of the flat.