The assistant forensic archaeologist, in his early thirties, only a small part of his face visible, said, ‘The soil in the grave is quite loose and there appears to be recent disturbance, which indicates to me that it was probably dug earlier and then back-filled not that long ago.’

‘Planned and made ready?’ Grace asked. ‘Is that what you’re saying?’

‘Yes, sir – that’s how it looks to me.’

‘What have you found?’

‘Well, sir, apart from the items of clothing we’ve retrieved so far, some of which have been sent by Sergeant Dennison-Wilkins to the lab for analysis, the grave contained traces of blood and lots of evidence of animal disturbance. And as I believe you’ve been told, we discovered a bone nearby just over an hour ago, it may have been dragged away by animals.’

‘Human?’

‘Possibly – we can’t be sure at this stage. Would you like to see it, sir?’

‘I’m no anatomy expert, but yes.’

Grace and Branson walked behind Lorna and Simon along more track to the smaller tent. The forensic archaeologist picked an evidence bag from the table, which contained a clean bone with a gnarled double lump at one end and a skewed knot at the other. Both ends appeared to have been chewed.

The detectives studied it carefully. ‘Humans have two lowerarm bones, if I’m right?’ Grace said.

Simon nodded. ‘The radius is one of two forearm bones – it’s the shorter of the two but thicker than the other, the ulna. It runs from the lateral side of the elbow to the thumb side of the wrist, and parallel to the ulna.’

Grace looked at it again for some moments. ‘You’ve sent a photo of it to Dundee for verification, I understand?’

‘Yes, they’re pretty good about coming back quickly.’

‘What’s your own assessment of the bone, Simon?’ he asked.

‘Well, Lucy’s the expert. In my view this could be human, but it might well be a roe deer tibia – this forest is home to a large number of deer.’

Grace continued studying the bone, none the wiser. ‘The fact that there are no body parts present in the grave could be put down to predation.’ He looked at Lorna and Simon for confirmation. Both nodded.

‘A dismembered body, especially in woodlands like this, can be carried off by animals within days – even more so if the grave is on a fox or badger run. But bones picked as clean as this, in less than a week? It’s possible, I guess – do you agree?’

‘It is, I – we – have seen it happen, sir,’ Lorna said. ‘Especially underwater. And, of course, acid is always a possibility.’

Grace had worked with Lorna in the past when she had been in charge of the now disbanded Sussex Police Specialist Search Unit. He’d seen instances of human bodies on the seabed being picked clean by fish and crustaceans in a very short time. And he’d seen his share of skeletal remains in acid baths.