‘Shit,’ Erika said, leaning over the desk to peer at the article.

‘Look, they’ve even done a supplement,’ Woolf said, pulling out a glossy black magazine with a giant picture of Jack Hart staring into the camera. ‘RIP’ was written above his head ‘You can’t touch it without getting your hands dirty,’ moaned Woolf, showing where the black ink had left a murky residue on his hand.

‘Maybe that’s a metaphor,’ said Erika, as she swiped her card on the door.

‘Do you really think a woman killed him?’ asked Woolf, his brow furrowing.

‘Yes,’ Erika said, pulling open the door and moving through into the station.

The air conditioning had been fixed in the conference room, which only added to the chilly atmosphere. Around the long table sat Erika, Chief Superintendent Marsh, Colleen Scanlan, Tim Aiken, the criminal psychologist and Assistant Commissioner Oakley.

Oakley cut straight to the chase. ‘DCI Foster, it greatly troubles me that you have reached the conclusion that these murders were committed by a woman.’

‘Sir, there are female serial killers,’ replied Erika.

‘I know that! It’s just that the evidence in this case is paper-thin. We have DNA from an ear print on the back door of Jack Hart’s house…’

‘Sir, we also managed to glean skin cells from the bag placed over Jack Hart’s head. It took him several minutes to asphyxiate, and we believe he thrashed around, striking the killer in the face.’

Oakley cocked his head to one side and was silent. Erika knew this to be a technique of his, to remain silent. It often caused the person he was questioning to babble, or to blurt something out which Oakley could later use to strengthen his argument. Erika remained silent.

‘I’d be keen to hear what Tim can bring to the table,’ said Oakley, turning his gaze on the criminal psychologist. Tim looked up from where he was writing on his pad. His hair jutted upwards from his head, and he had several days’ stubble.

‘The only compelling evidence that this is a woman comes from two sources. The ear print on the back door, and the plastic bag. This could be explained in many ways. The door had recently been repainted, six weeks before the murder: the print could have been left by one of the workers. There was a case a few years back of an ear print being used in a court case for a home invasion which led to the murder of a man and his wife. The ear print was used to prosecute a man who, it later turned out, had been working legitimately at the property as a plumber.’

‘And how do you explain the plastic bag?’ asked Erika.

‘The utility room is where Jack Hart kept his DIY and garden supplies. In the crime scene report, it states that there were two drawers containing bin liners, plastic freezer bags and old newspapers. It’s feasible that the same painter-decorator could have opened these drawers and contaminated the plastic bag with her DNA.’

‘The murder weapon wasn’t just an ordinary plastic bag. It was a suicide bag, or exit bag. A specialist item which has to be ordered online.’

‘Yes, and this suicide bag is much like the industrial plastic and zip lock bags used around the home, in DIY. Leaving the physical evidence to one side for a moment, the profile is more aligned to a male murderer. We shouldn’t forget that with the first victim, Gregory Munro, there was a homosexual element to the killing… And both victims were found naked in bed. I don’t wish to revert to stereotypes, but female serial killers are incredibly rare, and we need more concrete evidence before we abandon the theory that this is a single white male.’

‘So you’re saying we should ignore forensic evidence and concentrate on statistics?’ asked Erika.

‘The coverage in the media is extensive,’ interrupted Colleen, who had a stack of the day’s newspapers in front of her. ‘We need to make a statement, and this is what they call silly season in the press. There isn’t a lot else going on, besides coverage of this heatwave. A serial killer story is going to run and run.’

‘I believe that a woman is responsible for these killings,’ said Erika. ‘If the ear print on the outside of the back door were the only DNA evidence, then I would propose we were cautious. But the female DNA is on the bag used to kill Jack Hart, and very shortly we will have more details about the supplier of this bag – a website which has agreed to hand over the details of purchasers. We have more of a chance of catching the killer if we make the focus of our enquiries a woman. I am suggesting that we do a reconstruction. I’d like Colleen to contact the BBC Crimewatch programme. They are due to broadcast their monthly show in a few days. We can reconstruct Gregory Munro and Jack Hart’s last movements in the lead-up to their murders.’