She already knew the answer. But she didn’t want it to be true. She didn’t want the symbols and altars to be relevant or connected. It reminded her too much of The Teacher, who left signals for her team to find, to join the dots. Everything pointed to a Pagan type of sacrifice or ritual and with this in mind, she’d have to get her team together to work from that as their core motive. The symbols on the animals were convincing, but with this added communication from Mary’s killer, it was about as solid a lead as they got. She remembered, as part of the investigation into The Teacher, they’d discovered previous spates of killings dating back decades. Some of the older ones, in Yorkshire, she thought, had been religious in nature and symbolism. Amy Richmond had been killing all her life. Had she taken an apprentice that none of them knew about?

Mary’s killer was glorifying his or her work, and enjoying it. She looked back at the screen and to Mary’s mutilated body. She heard Dr Demi Cramer’s voice in her head. Demi had once given a lecture, which Kelly attended, years ago, when she was studying the forensic paper of her detective exams. She’d thought the woman a legend back then too. The lecture had been called ‘Serial Apprentice’ and it was Demi’s own phrase for how killers developed. Murder had been a commonplace mishap of humankind for thousands of years. Passion, arguments, love, hate, rage, jealousy and sex all collided in the mind, to produce such an alarming wave of violence that murderers often forgot the actual moment of the crime. Occasionally, though, one came across a killer whose Modus Operandi boasted such skill and composure that it was obvious that the planning and preparation was as important as the delivery of the event.

The Teacher was a good example. Kelly couldn’t help thinking that this was the reason why she’d had more correspondence of late from the nutcase languishing in Broadmoor at Her Majesty’s pleasure. The Teacher had been used by Demi to write a book, with Kelly’s blessing, and it was a fine piece of work: a bestseller in fact. Who better to recognise a fellow crazy than Amy Richmond?

‘Ted, can I call you back?’

‘Of course, but one more thing. When we re-examined Mary Hales this morning after noticing the mark, it was clear to us that it had been made at the same time as the knife wounds. It wasn’t an old tattoo, it was done that night. We’re trying to work out what sort of ink or equipment was used but no luck so far.’