She handed the piece of metal back to Hennessey.

‘Thanks, Dr D’Acre.’ Hennessey slipped the scaffolding pipe back into the holdall he had used to carry it from his car into the hospital, to the department of pathology.

‘Why pick on a length of scaffolding as the murder weapon?’

‘Oh, just that one of our suspects was seen and heard threatening Mr Williams with just such an object.’

‘Fair enough, but the murder weapon, if you find it, will be covered with blood and hair and possibly slivers of bone from Mrs Williams. I was able to obtain some grit and oil from the back of the heads of both the Williamses.’

‘Really?’

‘Yes. Would have faxed you, still will, but I did note that they were laid face up on a cold surface soon after death, that accounts for the hypostasis on the posterior aspects of both bodies. If there is a garage adjoining their home, then that’s where they were laid.’

‘There is.’

‘Might be worth getting the Scene of Crime people to give it the once-over.’

‘Might well.’

‘So you’ve got a suspect already?’

‘Got two, in fact. Both have motives and Sergeant Yellich has had the inspired notion that if we can link the two together, then we can really build a case, at least we can begin to. The only problem is that they’re not going to cough and neither of them are alibi merchants. They know the value of leaving the burden of proof with the police.’

‘Hard life you have. If my customers don’t tell me what I need to know, I can always put them back on ice, and pick my colleagues’ brains, or just leave them until medical science advances and tells us…oh…I’m sorry…’

‘No problem.’ Hennessey smiled. ‘Don’t worry about it.’

Thursday afternoon

…in which Sergeant Yellich feels he travels back in time and Chief Inspector Hennessey meets a pleasantly unpleasant individual.

‘A bit like Humpty Dumpty before the fall.’ Yellich swilled his coffee around in his mug. ‘Milady’s view of the world is a little askew, as is her view of her place in it.’

‘Sounds like it.’

‘When her eyes are opened, she’ll have a great fall and she just won’t get put together again no matter how many horses and men His Highness can offer.’

‘But there’s a link between Richardson and Sheringham. Your intuition is paying off, Sergeant. It’s paying off handsomely. Handsomely.’ Hennessey leaned forwards on his desk and beamed at Yellich. ‘We’re still a tad short of evidence though. I couldn’t hold Sheringham.’

‘Not even with the fingerprint in the bathroom?’

‘Not if he had been a regular visitor to the house. His solicitor jumped on that point, pounced, fell on it like a sparrow hawk.’

‘Fair enough, I suppose.’

‘Annoying though. But onwards and upwards - we’re getting there Yellich, we’re getting there. And the motivation is strong now, very strong, especially for Sheringham: he was scared that Max Williams was going to blow the whistle on him to the Drug Squad and he was scared that Amanda Williams was going to blow the whistle on him to his old lady. Makes him something of a Taipan in my mind.’

‘A what, sir?’

‘A Taipan, it’s an Australian snake. It’s just a nugget of information I stored away. You see, snake venom falls into two distinct categories, apparently. One that paralyses the nervous system, and one that coagulates the blood preventing it being pumped round the body.’

‘Blimey.’

‘As you say. The Taipan isn’t the most venomous snake in the world in terms of the strength of its poison, but it’s the only snake in the world whose venom is double acting. It both coagulates the blood of its victim, and paralyses the central nervous system and that makes it the most deadly snake in the world. Sheringham is like that, he’s got a double motivation.’

‘And Richardson too. He wasn’t a million miles from suspicion in the Kerr case, as you’ve pointed out. A man who owed Richardson money is found in a field with his head smashed in and his brains sticking out. And now Williams owes Richardson money and his head is also smashed to a pulp. That’s too much of a coincidence, Sergeant. And both would, in a sense, be more angry with Max Williams than Amanda.’

‘That would tie in with what Dr D’Acre said. You know, Mr Williams was murdered passionately, Mrs Williams coldly. One single, neat blow to the head would enable Sheringham to sleep at night. But Richardson’s anger would make him want to repeatedly batter Max Williams, and keep battering him, long after he’s dead. Then they team up and tidy the house, sanitize the crime scene and dig the grave, easy job for men built like they’re built. Pity they’re not stupid enough to alibi each other.’

‘We’ve still got to get the Crown Prosecution Service to run with it, it’s not for nothing that the GPS is known as the Criminal Protection Society in the canteen and the Police Club.’ Hennessey paused. ‘You look worried, Yellich.’

‘I am. It’s the cleaning of the house, sir.’

‘What about it?’

‘Well, it’s not actually politically correct.’

‘Cleaning a house?’

‘No…my point. It’s not politically correct.’

‘Come on, within these four walls, out with it.’

‘Well, boss, it has a woman’s touch to it.’

Hennessey paused. ‘It does, doesn’t it?’

‘I just can’t see the likes of Richardson or Sheringham being efficient with a cloth and a bottle of disinfectant.’

‘I can’t either.’

‘Mrs Richardson!’ Both men spoke at once and held eye contact as they did so.

Hennessey completed it for both of them. ‘It was her livelihood that went down the tubes as well. By the sounds of it, Mrs Sheringham would be more likely to murder her husband than either of the Williamses, nor can I see her being handy with the housework, that sort always has a “woman who does”. Is that the phrase?’

‘Mrs Richardson claims she was in Ireland over the weekend. If that alibi can be broken we’re on our way, boss.’

‘We are indeed.’

‘So what do we do now, boss, pick her up?’

‘Yes.’ Hennessey sat back in his chair. ‘Or do we? I wonder? No. Look, you seem to have a way with the ladies…’

‘I wouldn’t say that, boss.’ Yellich grinned.

‘You did well with Mrs Sheringham, you got the measure of her, all right. Go and see Mrs Richardson, take the measure of her. Me, I’m going to Selby.’

‘Selby?’

‘Selby. “Shored-up” has contacted me. Reckons he’s got information to sell. You know him and his games…but he’s come up with the goods before. And the weather’s fine, and Selby’s a pleasant little town. It’s certainly better than the last place we met. Have you ever been to Doncaster on a rainy day in January?’

‘No, can’t say I have, boss.’

‘Don’t. When you’ve seen her, visit his bank.’

Yellich had to keep reminding himself to keep an open mind.

The phrase ‘salt of the earth’ kept occurring to him when he spoke to Mrs Richardson. Yet he was all too well aware that the most unlikely people had committed desperate, terrible crimes. In his early days as a fresh-faced constable, he had allowed first impressions to cloud his judgement and let possible suspects go on their way only to find later that they had committed the crime in question and had slithered out of the arms of the law with a display of relaxed innocence. Only now, with some years’ service behind him, did he accept that everybody can commit crime, and even the most unlikely person will do so. Reluctantly, he accepted the police-canteen culture which states that, “They’re all guilty unless you know otherwise. And I mean know.”

‘There’s no point in denying it, son.’ Colleen Richardson was a tall, well-built, large-boned woman, who sat in a leather armchair in the front room of her Georgian-style house at the entrance of a new build estate on the edge of Huntingdon.