‘This is all wild speculation at the moment, anyway,’ Stanley said.

‘Finding the knife with a broken tip would be good,’ Boon said enthusiastically.

‘If she was murdered in the 1800s, it will be long gone,’ Stanley retorted.

‘It might be buried somewhere in the old convent grounds. We could use one of those metal detector things to look for it,’ Boon suggested.

‘A mechanical fit between the knife blade and broken tip would prove it was the murder weapon,’ Jane added, and Lloyd agreed.

Stanley shook his head, ‘searching the old convent grounds would take weeks, if not months. Spending a fortune on a murder that could have happened in the last century might not be justifiable, especially if the killer and any witnesses are all dead.’

‘So, we just forget about it . . . is that what you’re saying?’ Jane asked.

‘Like I said, Jane, I don’t make the decisions.’

‘Well, the coroner may want a full investigation. As I see it, the priority has to be to find out who the poor woman is,’ Jane said.

‘I think the coroner is likely to agree with DCS Barnes’s thoughts rather than yours,’ Stanley replied.

‘I’m not qualified in forensic odontology, but I can say her teeth are in reasonably good condition, which may help to give you her age range,’ Pullen interjected. ‘I can contact Dr Martin. He’s the top forensic odontologist in London and lectures at King’s College.’

‘Have they got an anthropology department?’ Jane asked.

‘Yes, they have,’ Pullen replied, ‘and they also have a senior lecturer there, Richard Eaves. He’s an expert in anatomical art and doing some ground-breaking work on facial reconstruction.’

‘What’s facial reconstruction?’ Boon asked.

‘Basically, he layers the skull of a body with modelling clay to create a three-dimensional facial likeness of the deceased person. It may lead to someone recognising the reconstructed face of the nun and help you identify her.’

Stanley raised his hand. ‘Slow down, the lot of you. Before we start calling every forensic expert in the phone book, let Dr Pullen finish the PM, then I’ll speak with Barnes.’

Pullen continued the post-mortem, dissected the body, and examined the internal organs, which had remained intact and become leathery due to the adipocere. The stomach contents had dried up, but there were some remnants of digested food which Pullen put in a glass container.

Pullen finished the post-mortem in nearly three hours. ‘Her liver, heart and other internal organs were preserved by the adipocere. They are all in good condition which makes me think she was a healthy young woman . . . possibly aged between twenty and thirty, but don’t quote me on that. Cause of death is the stab wound to the back which severed the spinal cord. I’ll type up my report and send it to Jane in the next couple of days.’

‘Thanks, Sam. You’ve given us some interesting details to work on. You also did an excellent job on your first solo PM,’ Jane said.