‘To estimate height, we turn to bone measurements and regression equations.’ He seemed to sense the shuffling and muttering. ‘Yes, I know it sounds like scientific jargon. What it means is that we can predict stature from the length of the femur, for example. Multiply by one number, add another, and bingo. For Victim A, length of the left femur is forty-four centimetres. Using the stature calculation formulas, we estimate she stood between five feet one and a half inches and five feet four and a half.’

A few officers were at least making notes, having detected some facts in the doctor’s presentation.

‘And the skeleton?’ someone asked.

‘Yes, Victim B. You’d think we could just lay a skeleton out and measure it to get the victim’s height. But cartilage decays and shrinks after death, sometimes by several inches. In Victim B’s case, the femur is forty-eight centimetres, giving a height of between five feet six and a half inches and five feet nine and a half inches.’

‘How accurate are these ages and measurements, Doctor?’

‘I’m confident the estimates are accurate, within the parameters I’ve given you. But I’d like to urge the police officers present to be careful with their missing person reports when trying to make a match. Don’t assume any degree of accuracy there.’

‘Why not?’

‘Well, a lot of people don’t actually know how tall they are. Or they lie about it. Some would like to be a few inches taller, others a bit less tall. And of course, they don’t realize that their height changes when they age, so they can be giving the wrong height for themselves for years without knowing it. Besides, if you’re looking at a missing person report, ask yourself who provided the information? A spouse, a friend? Some of those figures could just be a wild guess.’

Jamieson took advantage of the silence he’d created to press on hurriedly with his final point.

‘And how long have the remains been buried, you’ll ask me. Well, an unembalmed adult body buried unprotected in ordinary soil will normally take ten to twelve years to decompose down to a skeleton. Burial depth and soil temperature might vary the decomposition rate. A body in air decomposes eight times faster than when buried.’ He looked up from his laptop. ‘Like Detective Constable Cooper’s dead sheep.’

Gavin Murfin laughed, but no one else seemed to understand the joke. The anthropologist moved on rapidly.

‘When bodies are exposed to cool, moist soil, the soft tissues can decay quite slowly and turn into adipocere. Adipocere is a soapy, greasy substance that forms when body fat decomposes in a damp environment. It’s sometimes called grave wax. Adipocere is the cheesy greyish-white mass you can see in this photograph.’