He was equally unhappy about officers from the DPS coming to see him shortly after he had been appointed to inform him that one of his DIs was under investigation and that she should be kept away from any sensitive parts of the inquiry.

Collins had since been given the all-clear, but Anderson was in no hurry to make her part of his core team. He was all too well aware that he had gained a reputation for being something of a misogynist but knew that in reality it was entirely undeserved. Some of the female officers he had worked with in the past had been razor-sharp and excellent. Others, however, had been absolutely hopeless. But exactly the same could be said of the men he had worked with.

The simple truth was that good officers, regardless of gender, ethnicity or disability, were thin on the ground. He didn’t plan to let anyone drop the ball on one of his cases, least of all Collins.

Anderson paused and steepled his fingers. ‘I was having a chat with DCS Higgins the other day and your name came up.’

Collins said nothing. Instead she waited for Anderson to carry on.

‘He rates you very highly,’ he said at last. ‘He told me to be sure to make the most of you, that you’d be a real asset. He was sorry to see you go.’

‘I was sorry to leave,’ Collins replied.

‘It’s clear you two had a pretty special relationship.’

‘I wasn’t sleeping with him if that’s what you’re getting at.’

‘I wasn’t. Not at all. I mean it’s clear that he empathized with your way of doing things. It’s also clear that I do things very differently. You’re just going to have to get used to that.’

‘So it would appear.’

‘I run a tight ship, Collins,’ he said. ‘There isn’t any room for mavericks in my team. If you take one step out of line, you’re off the squad. Do I make myself clear?’

Collins leaned forward and placed both palms flat down on the desk. ‘Listen, I want to get whoever is responsible for these murders every bit as much as you do. I’m going to do my job to the best of my ability. That’s all I ever do. I’ll always put the case first. You might surround yourself with yes men who’ll take the fall for you if you mess up an investigation and maybe it pisses you off that I’m not like that, but, like I said, I put the case before my own career and I certainly put it before yours.’

Anderson was staring hard at Collins. ‘You didn’t answer my question, Collins. One wrong move from you and you won’t just be off my team, you’ll be out of MIT altogether. Do I make myself clear?’

Collins stepped back and folded her arms in front of her body. It was the most defiant gesture she could make under the circumstances.

‘Yes, sir. Crystal.’

Collins stared silently out of the side window of the squad car taking her, Hill and Anderson to Guy’s Hospital, where the post-mortem was due to take place. She sat in the back alongside Hill while the DCI was up in front next to the driver.

The first few minutes passed in silence but then Anderson folded up the newspaper he had been reading, turned to Collins and smiled. ‘So, you’re a tad sceptical about the chances of Leroy Banks being involved.’

Collins was taken aback by both the question and Anderson’s friendly tone but rapidly regained her composure. ‘I just don’t think he’s serial killer material. I know he has motive for wanting to attack Edward Miller, but I don’t see him going as far as killing him, let alone the other two. You don’t seriously think he’s involved, do you?’

Anderson smiled again and Collins realized that this was probably the first time she had ever seen him do so. ‘I don’t like to leave any stone unturned,’ he said, ‘just in case it comes back and bites me on the arse, if you’ll forgive my mixed metaphors.

‘One of my first murder cases involved this teenage girl who had been stabbed to death in her own home. I got to the scene and it was a terrible mess. Blood everywhere, a real frenzied attack.

‘There was no sign of a forced entry, and the only people in the house were the mother – she called it in – the stepfather and the girl’s younger brother. When we went into the brother’s room we all had a bit of a shock. He was one of those death-obsessed teenagers. Every square inch of the wall was covered in posters for slasher films, heavy-metal music and vampire memorabilia. There were skulls and crucifixes everywhere, as well as a load of marijuana and speed.

‘Everyone on the team liked the kid for the killing, and there was a suspicion that the stepfather might have helped. It looked like an open-and-shut case but my guv was less sure. Made us do a trawl of the neighbourhood. That was when we found a homeless guy, care-in-the-community case, wandering around in a drunken stupor. He had no blood on him and no weapon, and there would have been no way that he could have entered the house. The only things in his pockets were a couple of chocolate bars. I was all for letting him go but the guv said we had to bring him in anyway to cover all the bases.

‘Cut a long story short, it was the homeless guy that did it. To this day we don’t know how he managed to get into the house but what we do know is that he stabbed the girl while she was in her bed so her blood got soaked up by the duvet. We found a tiny spot on his sweatshirt but what had really nailed it was that the governor had noticed a little bowl full of chocolate bars by the side of the girl’s bed. The guy had nicked a handful on his way out. Ever since, I like to bring in as many people as I can – isn’t that right, Len?’

DI Hill nodded with a grin. ‘Right pain in the arse it is too, but more often than not it pays dividends.’

Anderson still had a smile as he turned away from Collins but it slowly started to fade from his lips. ‘Funny thinking back to that old case,’ he said wistfully. ‘Somehow I don’t think this one is going to be anywhere near as easy to solve.’

*

Ten minutes later the three officers, all wearing their protective gowns and masks, were following Dr Matthews into the chilly hospital mortuary. Just before entering the room Collins placed a swimming peg on the end of her nose, forcing her to breathe through her mouth. It made her look and sound a bit ridiculous, but the smell of decay was one she had no desire to get used to.

All three bodies had been brought out of storage and each one was lying flat on a stainless-steel table covered by a green plastic sheet. Matthews headed to the nearest table and stood on one side of it, inviting the three officers to stand opposite her.

‘We’ll begin with Raymond Chadwick,’ she said. ‘Now, as I am sure you know, there are usually five stages to the autopsy process: the Y-incision, followed by the removal of the organs, examination of the stomach contents, collection of samples, and finally examination of the head and brain.’

Matthews reached out and pulled back the green plastic sheet with a flourish to reveal the body underneath. ‘But, as you can see,’ she said, ‘most of that does not apply to the current cases.’

Chadwick had been straightened out from the foetal position and now lay flat on his back. He was completely naked and his skin had taken on a pale green-grey tinge. A brown, soupy fluid was seeping out from the base of his body. Collins noted with alarm that the tiny white maggots she had observed in his chest and neck at the crime scene seemed to have grown. ‘Aren’t they potentially destroying evidence?’ Collins said, pointing at the mass of white worms.

Matthews followed her gaze. ‘Potentially, but getting rid of them before I’ve carried out my examination would be far more damaging. It’s too cold in storage for flies to lay eggs, but if a body comes in already infested there really isn’t very much that we can do. In this case, the amount of raw flesh on the body has proved particularly attractive to the little blighters. We’ll wash him down when I’m finished, but I can’t do it now; otherwise I might wash away trace evidence.’