‘And where is Mr Lal now?’ Michelle asked.

‘I have no idea.’

‘You told us he had a key to your house. Did he stay here in the last few days?’

‘No.’

‘Where do you think Mr Lal would go?’ she asked.

‘I don’t know. But he’ll turn up again in a few days. He’s done this before, running off when upset.’

‘His car was found in Guildford. Do you know who he might know there?’ she continued.

Morag shook her head.

‘Did he stay with you in February last year?’ Gillard asked.

She hesitated. ‘No, I don’t think so.’

‘Did anyone stay at that time? From the third to the ninth?’ he continued.

‘No, it was just me and my son.’ She smiled.

‘Not Harry?’

‘No. We’d got past that particular cover-up routine by then.’

Gillard eyed another brownie, and Morag encouraged them both to take more. ‘Well, Ms Fairburn, that is odd, because we’ve found something very interesting on your Internet search history between the third and ninth of February last year,’ Gillard said, as he took a bite.

For the first time Morag looked nervous. She had to wait a full half minute as Gillard gave the delicious sticky morsel the full thirty-two slow chews that his mother had always told him was required for perfect digestion. Finally swallowing, he said: ‘Your home computer was used to search for details about the toxic metal thallium. Half a dozen references, over a number of days.’ He took another bite of the brownie. ‘These are delicious, by the way,’ he said, gesturing to the crumbs on his plate. ‘Are they home-made?’

Morag licked her lips. It was clearly nothing to do with the prospect of more food. She looked even paler than he had ever seen her, a blueish vein on her temple prominent and pulsing.

‘Did you make those searches?’ His question was no less tricky for being obvious.

She barely hesitated. ‘No, it wasn’t me. And it wasn’t my son either.’

‘So if, as you say, you were here alone, who could it possibly have been?’

She didn’t reply.

Gillard shook his head. ‘It seems that for all of your sweet and accommodating nature, you have become an almost compulsive liar.’ He pointed at the emerald ring. ‘Though you have of course been well rewarded for it.’

‘Harry appreciates my loyalty.’

‘Well, I appreciate loyalty too, particularly to the truth, and I’m entitled to expect it from witnesses. So I’m afraid we’re going to have another interview, this time at a police station. I think you should bring your solicitor.’

She nodded.

He gestured to Michelle Tsu that they were leaving. ‘Thank you for the brownies, by the way. Very tasty.’ They left, hearing her tears begin before they had exited the front door.

Tweedledum and Tweedledee, a.k.a. DC Colin Hodges and DC Carl Hoskins, were enjoying a full cooked breakfast in Mount Browne’s refectory on the Friday morning after a pulling an all-nighter looking at CCTV of Guildford town centre trying to find where Zayan Lal had disappeared to.