Financial checks painted a similar picture of probity and hard work. Iqbal declared all his earnings, wasn’t a big spender, had no credit card or store card debt, and he even gave 10 per cent of his income to charity. Despite this generosity, he lived so modestly that when he died he had nearly £23,000 in his bank account. Apparently Iqbal had been saving to buy a boat to keep on the Thames at Marlow. He’d been well on the way to that dream when he’d died.

As for the autopsy, the preliminary results showed he’d had no alcohol in his system when he’d died, although there’d been significant traces of Diphenazine, the brand of sleeping pills they’d found in Iqbal’s bedroom. However, the dosage was well within safe limits. As far as the forensic toxicologist was concerned, it would have been enough to make Iqbal woozy but no more. Nonetheless, as it was a prescription drug, DS Malik rang Iqbal’s GP, who confirmed that Mr Kassam had asked for help with sleeping the year before. He’d been working a lot of nights and he was struggling to sleep during the day.

This information gave DS Malik pause. After all, there’d been no break-in before the murder, or signs of a struggle for that matter. So, the fact that Iqbal was shot in bed while drugged on sleeping pills made it very unlikely that he’d got up to let the killer in.

This theory was given further credence by the pathologist’s assertion that Iqbal had died between 5 and 6 a.m. This fitted with Iqbal’s diary, which showed that he’d been working until 3 a.m. on the night of his death. It seemed most likely that he’d come off shift at 3 a.m., got home, gone to bed, found he couldn’t sleep and taken a dose of sleeping pills to help him on his way. Then the killer had let himself into Iqbal’s house with a spare key and killed him sometime between 5 and 6 a.m.

But if the killer had a spare key, then that suggested that Iqbal had considered him a close and trusted friend. After all, Iqbal hadn’t been prepared to give a spare key to his dog walker.

But no matter how hard DS Malik and her team hunted, there was nothing in Iqbal’s diary, emails, phone and financial records or more general correspondence that suggested he had any regular friends. In fact, DS Malik and her team struggled to find anyone who knew him at all. As Suzie had told them, Iqbal was an only child and his parents had died many years ago.

There were only two meaningful leads.