He’d barely eaten half the breakfast when a call came through. It was Yaz Quoroshi inviting him to inspect the murder weapon at close hand. Gillard stood and made his excuses to the CSI trainees, and after crossing the internal courtyard made his way to the specialist forensic centre. With more than thirty employees, Mount Browne’s forensic unit was able to process many of the simple forensic tests which detected the presence of DNA, saliva, blood or semen. Only the more complex comparisons, of DNA against the national database for example, needed to be undertaken by an external lab. The detective pressed his pass against the entry panel, and after the door opened, walked down the wood-lined corridor towards the lab.

Quoroshi welcomed him. The silvery gym weight, one end encrusted with dried blood and hair, was sitting on a sheet of plastic. ‘It’s a hefty weapon at one kilo just for the bar, with those two screw-ons doubling its weight,’ he said, pointing a latex glove. ‘I can see that it had a fair bit of use during its life, and I’m hopeful some of the sweat and oil residue will have become trapped in the thread ridges. But first of all I have to check for prints.’ From a drawer he took out a thick roll of tape, and easing out a foot-long piece, pressed it carefully around the shaft of the metal. ‘This is gel lift tape. Absolutely magic for this kind of uneven surface.’ He set the tape aside carefully, then pulled out some cotton buds and ran them carefully up and down the thread and knurls of the hand weight. ‘I just want to see if there’s enough DNA for a match. Potentially it could survive on a surface like this for up to six weeks, which could mean that if anybody else had previously used the weights, their own markers could be present too. So even if the assailant used gloves in the actual attack, we might get him or an associate from a previous contact with the item.’

The late Mrs Tanvi Roy may have owned a grand house in Richmond, but her PA Philippa Boswell had mentioned that she spent as much time in a modest and anonymous two-bedroom ground floor flat on the edges of Leatherhead, just a few miles from Ashtead Common. It was within easy reach of the company’s Redhill factory, where a new range of snacks was being launched, and Mrs Boswell said Mrs Roy had on the final night before her death rung her from there to say she would be staying there the next two evenings.

Gillard had obtained the keys to the flat from the family, and with a local uniformed constable outside to keep watch, he put on a Tyvek suit, gloves and booties, and let himself in. He picked up a stack of mail and put it to one side as he stepped into the modern hallway. The kitchen/diner to the right was neat, with just a single teaspoon in the drainer, and tea towels neatly hung in a row. He opened the fridge and peered within. There was a considerable array of gin and tonic, some fruit yoghurts and some other health food that he couldn’t readily identify. But the biggest surprise was a collection of six jam jars, with handwritten date labels on, all within the last two weeks. It looked like they contained apple juice or something similar. He unscrewed one and took a sniff.