They made it in under ten minutes, leaving the car down the road, one side of which had been blocked off as a tent was erected to give some privacy at street level. Easter Road led out of the city towards Leith. The area was suffering a sad decline, and the three-storey housing featured sheets hung in place of curtains and window frames that had lost more paint than remained on them. The flat in question was on the second floor with a shared entrance hall.

Ava and Callanach donned white suits, shoe covers, gloves and hats, and prepared to enter. A sulphuric, metallic smell gave the situation away from the first-floor landing. The body had been there a while. The weather was so cold that unless the flat had been heated to an extreme, the smell would have taken a while to get so strong.

Ailsa Lambert appeared at the front door of the flat, talking brusquely to a member of her team and handing over a camera.

‘You ready for us to come in and take a look?’ Ava asked her.

‘Go ahead,’ Ailsa replied shortly.

Ava and Callanach shared a brief look. If Ailsa was out of sorts, then whatever was waiting for them had to be bad.

The bathroom was tiny and the forensics team cleared out to allow them access. Ava stood with her back against the window and Callanach spread his legs either side of the toilet so they could both look down into the bath. Tripp appeared in the doorway as they were taking stock.

‘Who reported it?’ Ava asked him.

‘A neighbour,’ Tripp replied. ‘The smell had been getting worse over two weeks, so he finally called the police.’

‘Two weeks?’ Ava hissed. ‘Are you kidding?’

‘Afraid not. I suspect the neighbour might be selling some weed on an informal scale judging by the smell of his own apartment and the fact that while I was talking to him, his mobile rang repeatedly. He’d obviously just cleaned off every surface in his flat but neglected to cover up the scales on the floor in the corner.’

‘So he didn’t want the police in here until it got to the stage where the stench was actually affecting his clientele, is that it?’

‘Something like that, ma’am,’ Tripp replied. ‘The pathologist confirmed the body’s been here at least two weeks, more likely three. Judging by the photos on the walls, I’d say the deceased is the owner and resident, a Mrs Hawksmith.’