Gillard thanked him and they exchanged contact details before ending the call.

‘Useful?’ Christina asked.

‘Possibly,’ Gillard said. ‘It adds weight to the idea of a motive within the family. If there were strategic differences about what to do with the company.’ He returned her phone and pulled out his own. ‘I’m going to get onto my own financial detective expert, DS Shireen Corey-Williams. She’s going to love sinking her teeth into this.’

It was after ten p.m. by the time Gillard got back home. Sam was watching TV and shushed him when he started to speak. ‘I’m sure you want to see this. It’s a special, all about Mrs Roy and the Empire of Spice.’

He sighed and sat down with her. ‘I suppose I’d better watch it.’ He caressed her tummy. ‘How’s everything?’ Sam was nine weeks pregnant, and had been troubled by nausea and morning sickness. She’d miscarried on a previous occasion at ten weeks a year ago, and was understandably anxious about a repetition.

‘Fine.’ She pressed a finger to her husband’s lips, as she looked at the screen.

‘The murder of Mrs Tanvi Roy on Sunday morning has shocked the nation,’ the presenter said, anoraked against the sleet and standing in front of a floodlit crime scene. Beyond the blue fluttering tape, figures in Tyvek suits were busy coming and going to a large plastic marquee which trembled in the wind. ‘She was the matriarch of one of Britain’s best-known ethnic food companies, a frequent TV chef and celebrity, and was held in great esteem by hundreds of thousands of viewers who tuned in not only to BBC’s Celebrity Cook Off, but also saw her fronting advertisements for the bestselling products from her family company, Empire of Spice.’

Gillard watched as three of the most famous advertisements were shown in brief, and then a snippet from a cookery show, which showed a bustling but stylish woman, her dark hair cut in a neat bob, rapidly folding pieces of precisely cut pastry, adding a few dabs of filling, then skilfully folding them into a triangle. ‘And there you are, spicy mini samosas, ready for baking and perfect to add a bit of zing to any dinner,’ she said to camera, then gestured to a small bowl. ‘And here of course is the perfect creamy mint-infused dip, to balance out the heat with the cool.’

The next image was a black and white photo of an Indian family. The presenter, in voice-over, said, ‘So how did this successful business begin? Well, the roots were, perhaps surprisingly, in Africa. The young Tanvi, her three brothers and sisters and her parents fled in 1972 from Idi Amin’s Uganda with just five pounds to the family name. They settled in Leicester with an aunt, where they all worked in the family sub-post office. Within two years, and using savings borrowed from the wider family, they set up a small shop in the centre of the East Midlands city. The young Tanvi was wooed by an old acquaintance of the family and in 1976, aged eighteen, she was married to a forty-eight-year-old academic, Dr L. K. Roy, and moved down to Slough, where he had inherited a long-established spice import/export business. Her flair for numbers and a capacity for hard work soon made her husband realise that she would be an asset beyond the family home. It was she who suggested to him that her family’s recipes for pickles and chutneys might find favour in the rapidly expanding British taste for ethnic foods. They started slowly, but the business grew rapidly. By the start of the 1980s, the company already had its own manufacturing facilities and dozens of employees, and the brand Empire of Spice was becoming well known.’