The Dragon's Skin. Ross Gray

They’re the easy ones. We solve almost all of them. Even if we can’t get enough material evidence to make a case in court, we usually know who did it. Random, motiveless killing is harder. But it’s usually uncontrolled, unplanned, sloppy, and nine times out of ten someone dobs the killer in. Underworld killings?’ She shrugged. ‘Well, that’s more a case of who we know than what we know.’ She paused to sip her coffee.

      Carol watched her eyes over the rim of her cup and said nothing. She knew she was rehearsing this as a prologue to something else. And she kept saying ‘we’.

      ‘Then there’s our serial killer. Apparently random, if we can’t detect the pattern. Nothing but a symbolic connection to the victim, and then, only in the fantasies of the killer. The best we can hope for is that he wants to get caught or we get lucky. We have to wait until he’s killed so many that he becomes over-confident, someone who knows him smells a rat, or we accumulate enough data to identify or anticipate him.’ She took another muffin from the pile and began to pull it gently apart, popping bite-sized pieces in her mouth. ‘There are so few serial killings in this country that they hardly register as a statistic.’ She popped another piece of muffin. ‘Of course, contract killings aren’t top of the pops either.’

      Carol was doing a detective training course, she felt a sudden urge to show and tell. ‘Two percent of total murders,’ she said a little hurriedly. ‘According to recent research,’ she added feebly, as is if in apology for interrupting. The other Carol just smiled at her. ‘There’s between about seven and ten contracts a year in this country.’ There was still no response from across the table. She ploughed on. Much too breathlessly, she noticed. ‘Most of those aren’t cool professional hits. They’re usually crimes of passion. Someone in a broken relationship hires an amateur – occasionally a professional – to knock off a partner or the ex or the third party. Only about five contract killings per year are successfully completed. They’re usually professional ones.’

      ‘So,’ said her hostess. ‘You would argue that the statistics favour a “contract killer” hypothesis over a “serial killer” hypothesis in the Jogger Murders case?’ She flipped another bit of muffin, chewed, smiled, and said, ‘Interesting.’

      Carol began to wonder about her motives. Was the case an itch this wo­man could no longer reach? And was this tête-à-tête an audition for the role of back scratcher? If it was, Carol Marks’s next words implied that she’d won the part.

      ‘They weren’t treated as serial killings until the fourth murder. That’s when we got involved,’ she began. She sounded like an officer launching a briefing.

      ‘Fourth?’ Carol interrupted. ‘I thought there were only three.’

      ‘Officially, yes. But we – the three of us in Davy’s little group – always thought of it as four. Davy postulated that another, earlier, murder was part of the picture. He suggested that it was … practice.’ She faltered as if challenged by some memory or association. ‘A sort of dry run.’ Her smile was narrow and bleak. Her eyes were no longer cut-and-polished amethyst but dull stone. Her head tossed as if to shake cobwebs away then she leaned forward in her chair, renewed.

      ‘To begin at the beginning,’ she said. ‘Davy – Skid said you’ve met him?’ Carol nodded. ‘Davy was the lead on the third – or fourth – murder. Once the similarity to the others was established, and they were officially connected and recognised as serial killings, a taskforce was established. Davy and the detectives investigating the other murders were subsumed into it under Bruce Tolliday, a senior sergeant. Bruce was plodding, but always well organised, very careful, very thorough. You probably gathered that when you read his report. He was far from persuaded by Davy’s theory, but he held a high opinion of his ability, and Bruce wasn’t one to let a stone remain unturned. He gave Davy the green light to pursue his own line of inquiry and allowed him a couple of uniforms for the legwork. That’s where we came in, Jac and me.’