‘They were subdued with a date rape drug administered to an alcoholic drink inside their property, which aided the suffocation with the plastic bag,’ said Singh.

‘Yes, and it’s the same specific type of bag used in both murders. A “suicide” or “exit” bag. These are available to buy from specialist sites on the Internet. So we need to check out which sites sell them, and get a purchase history, a list of credit card transactions and addresses.’

‘They were both of a similar height,’ said Moss. ‘Gregory Munro was older, and wasn’t as fit and healthy as Jack Hart.’

‘The killer adjusted the dose for the size of his victims. Jack Hart was given a higher dose than Gregory Munro, so potentially he had studied them from afar,’ said Erika.

‘They were both stalked, at night,’ added Peterson.

‘Why do you use the word “stalked”?’

‘The killer could have already been inside their houses when they got home… He probably stalked them round the house, watched them. It might not have been the first time,’ said Peterson.

‘Yeah, it was planned. He staked out the houses beforehand. He mocked up a fake security firm leaflet for Gregory Munro; he knew how he was going to get into Jack Hart’s house,’ added Moss.

‘Maybe he’s ex-military? He left virtually no DNA evidence,’ said Singh.

‘Or he works in a hospital or pharmacy. He was able to get hold of liquid flunitrazepam and a syringe… We found the cap of a syringe under Jack Hart’s bed. Although you can get all that stuff off the Internet these days,’ said DC Warren.

‘That could link him to Gregory Munro,’ said Peterson.

‘But how does it link him to Jack Hart?’ said Erika.

‘There’s no history of gay relationships or a gay past with Jack?’ asked Peterson.

‘Not that we know of,’ said Erika. ‘His wife is going to formally identify the body later today, but obviously we need to tread easy when we question her. Gregory Munro has a son; Jack Hart has two small children. They’re both estranged from the mother. Has anyone got anything to say about that?’

There was silence.

‘There must be some reason why this guy is targeting these two men!’ said Erika, drawing a large black circle on the whiteboard around the photos of the two men.

‘But what the bloody hell does a local GP have in common with a tabloid TV presenter?’ asked Moss.

‘Well, we need to find that out, and fast,’ said Erika. ‘The link will be to the killer. Whoever this is, chose the victims. Watched them in the days leading up to the murders Now, there haven’t been any fingerprints recovered from either murder scene, or from Jack Hart’s next-door neighbour whose daughter’s nursery was broken into, but we did get an ear print from the outside of the back door at Jack Hart’s house. Have we had anything back, Crane, from – where is it again?’

‘The National Training Centre for Scientific Support to Crime Investigation,’ said Crane. ‘I’ve just heard that they’re about to run this through their database of over two thousand ear prints. So we could get a call any time.’

‘I’m not holding out much hope, but two thousand ears – those odds are better than I thought,’ said Erika.

‘I’ve just had the pictures back off the memory card we confiscated from the journalist,’ said Moss, looking at her computer.

‘Why has it taken so long?’ asked Erika.

‘The metal contacts were bent; the photographer probably bent them when he yanked the card out of the camera and swallowed it,’ she said.

‘Okay, let’s put them up on the projector,’ said Erika. DC Warren grabbed a multimedia projector off a shelf at the back of the incident room, went over to Moss’s PC and plugged it in. After a couple of minutes of positioning, they had it trained on the whiteboard.

Erika turned off the lights, plunging the room into darkness, and then an image of a car on a busy street, surrounded by people, appeared on the back wall.

‘Okay, boss, I’ll just go through these,’ said Moss, clicking with her mouse. A series of similar photos flashed by, and then some paparazzi pictures of an unknown celebrity leaving the Ivy restaurant in a car with tinted windows.

‘Okay, here we go. These are Jack Hart’s house.’

The first picture was of Jack Hart arriving back at his house on the night of his murder. Moss flicked through the images, taken in a rapid-fire, almost like jerky animation. Jack leaving the black cab, walking to his gate, opening it, stopping for a moment to turn and say something. Then Jack moving to his front door, reaching into his pocket and pulling his key out, opening the front door and going inside.