It was still before nine when he strode into the technical centre at the crime scene unit, and he saw there was just one young woman there, hunched over her screen. Hoskins asked her what Rob Townsend had most recently been working on, and after perusing the log she called up an electronic connection map. The officer explained that this piece of software logged all of the telephone, email and text connections between persons of interest in the case, colour-coded by date. It was a huge and rather beautiful image that filled the screen, with brightly coloured lines showing recent connections, but greying out for those older.

‘Can I add just a couple more numbers?’ Hoskins asked. ‘It’s just a hunch.’ He passed across one mobile and one landline number. The woman entered them on the system, and they both watched as the knot of connections reconfigured itself. ‘Anything?’

‘Hmm. Nothing on the mobile, but ah, we do have something.’ She cross-referenced the number. ‘Several calls from Deepak Tripathi to the landline. None going the other way.’ She called up the details on a separate screen. ‘Yes, several very short calls, around a week ago, possibly just leaving a message, and two much longer ones all within the last month.’ The officer looked over to the notebook from which Hoskins had the numbers scribbled down. ‘Give me the name and I’ll add it to the database,’ she said brightly.

‘Don’t worry.’ Hoskins pocketed his notebook, and thanked her for the help. ‘You can delete those numbers. I’ve got some checking to do first.’ Hoskins wasn’t about to disclose that he had been checking up on one of this woman’s newly qualified colleagues. But for all of that he couldn’t think of a single reason why Deepak Tripathi would be telephoning Kirsty Mockett.

Unless poison had something to do with it.

Chapter 24

Dr David Delahaye rang Gillard at six thirty on Saturday evening. The detective had promised Sam he would be home and stay home all evening. Now she was no longer pregnant, she could indulge herself in a glass of wine, but didn’t want to do so alone while waiting for her workaholic husband to get home.

‘Well, Craig, it’s not thallium,’ the pathologist said. ‘If that is good news. Fortunately they did some broad-spectrum testing, and it seems Mr Hodges kidney failure and cardiac arrest were brought on by a hefty dose of ethylene glycol.’

‘That’s antifreeze, isn’t it?’

‘Yes, but it’s also found in domestic radiator cleaners and a few other household products. It’s colourless and odourless but has a sweet taste, so it would be easily concealed in many foods.’

‘Like cake?’

‘Yes, amongst others. Although it is fairly toxic, if caught early enough there are effective treatments. While they put Mr Hodges on renal dialysis, they failed to make the additional checks which would have revealed the other symptoms. I suppose one can forgive them because there are many other reasons for a man who was bordering on obese to have kidney trouble.’