An officer’s notebooks could be invaluable when trying to reconstruct the pattern of an investigation, as could the action allocations, records made of all the instructions issued to investigating officers by the senior investigating officer. For example, if DC Higginbottom was asked to go and interview Joe Smith’s neighbor, that order, or “action,” would be recorded in the actions allocation book, and his record of the interview would be in his notebook. By looking at the actions, you could determine which areas of inquiry had been pursued and which had not, and by reading the notebooks you could unearth impressions that might not have made it into final statements and formal reports.

Completed notebooks were first handed to a detective inspector, who would look them over and, if everything was acceptable, send them to the records clerk for filing. That meant they piled up over the years. Whoever said we were heading for a paperless world, Michelle thought, as she walked along the rows of shelving stacked to the ceiling with boxes, obviously wasn’t a copper.

Mrs. Metcalfe showed her where the notebooks were filed, and Michelle went first, by instinct, to Ben Shaw’s. But no matter how many times she flipped through the boxes, checked and rechecked the dates, in the end she had to admit that if there had been notebooks covering the period of major activity in the Graham Marshall case, on the day of his disappearance, August 22, 1965, over the next month or two, then they had vanished.

Michelle found it difficult to decipher Shaw’s handwriting in the notebooks she did find, but she could just about make out that his last entry was on August 15, 1965, when he had been questioning a witness to a post office robbery, and the next one was a new notebook started on the sixth of October of the same year.

Michelle asked for Mrs. Metcalfe’s help, but after half an hour even the poor records clerk had to admit defeat. “I can’t imagine where they’ve got to, love,” she said. “Except they might have got misfiled by my predecessor, or lost in one of the moves.”

“Could someone have taken them?” Michelle asked.

“I don’t see who. Or why. I mean, it’s only people like you who come down here. Other police.”

Exactly what Michelle had been thinking. She could have taken out anything she wanted during her visits, and Mrs. Metcalfe would have been none the wiser. Which meant that anyone else could, too. Someone had gained entry to her flat and tried to scare her off the case, and now she found that nearly two months’ worth, a crucial two months’ worth, of notebooks had somehow disappeared. Coincidence? Michelle didn’t think so.

Half an hour later, when they had run into the same problem with the action allocation book for the Graham Marshall case, Michelle knew in her bones that the actions and the notebooks were gone forever, destroyed, most likely. But why? And by whom? The discovery didn’t help her paranoia one bit. She was beginning to feel way out of her depth. What the hell should she do now?