Sasha and her team sat listening as Ajay brought them up to speed on Gardner’s death, and looked at photos taken of the crime scene inside the house. Ajay dropped his notes on his desk.

‘He was hit multiple times on the head, we believe by a brick taken from the stack in the front garden, which was left by the body. Then the gas was left on, or a pipe tampered with – the fire investigators are still looking into the exact details of that – causing the explosion.’

‘The attack could have been a spur of the moment thing,’ said Craig. ‘There’s an argument on the doorstep. The killer picks up a murder weapon close to hand, a brick, and bashes him on the head with it.’

‘But they just happened to have acid in their pocket?’ Lolly made a face. ‘They were watching the place, more like. They knew the bricks were there all along. They knock on the door, Gardner opens it and gets a face full of acid.’ She mimed throwing it. ‘While he’s rolling around in agony, they walk in calm as you like, shut the door behind them and bosh, it’s easy enough to finish the job.’

‘This is all very interesting, Ajay.’ Sasha stirred a coffee. ‘But I’m still waiting for this bombshell you promised.’

‘Lots of DNA would have been obliterated in the fire but an interesting sample was found on the handle of the front door, which blew out. It’s a partial match for somebody we found in the database.’ He paused dramatically.

‘For goodness sake, Ajay,’ said Sasha impatiently. ‘This isn’t a quiz show, just tell us.’

‘The DNA is a partial match for Jeremy Weston.’

‘Wait, that’s it?’ Craig frowned. ‘It’s not beyond the realms of possibility that Weston visited Tony Gardner.’

‘No,’ Ajay told him. ‘That’s not what I said. The DNA is a partial match with Jeremy Weston’s, but it’s not his. It’s a fifty per cent match, and the profile has two X chromosomes, so it’s female.’

Sasha lifted her teaspoon from the mug, surprised by the unexpected left turn the briefing had taken.

‘What are you saying?’ asked Vaughn, who had been listening at the back of the room and now stepped closer.

‘It’s familial DNA, guv,’ Ajay told him, ‘suggesting a close female relative.’

‘In Tony’s house?’ asked Lolly.

‘And we have Weston’s DNA, how?’ asked Sasha.

‘Weston gave a DNA sample for a traffic offence a few months back,’ Ajay said.

Sasha nodded at Craig. ‘Let’s see if we can find a match on the offender database.’