The Thread of Evidence (12 page)

Dr Tom Mitchell, the anatomist, whose room this was, climbed to his feet and stood looking critically at his handiwork.

‘I'll have to shuffle them about a bit first, to allow for the cartilage of the joint spaces. That should give us the exact height then. What do you think of it, Leighton?'

The bald-headed forensic expert hauled himself off the floor and dusted down the knees of his suit as he looked at the grinning skull and loosely arranged bones on the sheet. As Meadows had said, the skeleton looked perfectly complete, the only odd feature being the thick, waxy flesh on the legs.

‘Yes, it looks OK,' he replied. ‘We may as well check our fancy calculations of the height by a direct measurement, I suppose.'

The tall, thin anatomist began arranging the bones with minute precision. He separated the rusty brown pieces one by one, starting at the neck, where the spinal bones joined the skull. The genial professor explained to Meadows what Mitchell was doing.

‘The idea is to allow for the thickness of the gristle between the vertebrae of the spine and the cartilage in the knee and hip joints. We've already calculated what her height should be during life, by applying special formulae to individual bones, especially in the leg. But it would be nice to check the answer by putting the bones in their “living” position and then running a tape measure over the whole lot.'

‘Wouldn't that be the best way, in any case?' asked Meadows.

Leighton Powell pursed his lips. ‘Not necessarily. It's difficult to get the bones to lie on a flat surface in the way they do in the body. The spine has three curves, more marked in women. You can't always reproduce that accurately with a heap of loose bones. But the main use of the calculation method is when only a part of the skeleton, or even only one bone, is available.'

Tom Mitchell straightened his own back for a moment and added his explanations. ‘More often than not, there are bones missing all over the skeleton. We're unusually lucky with this one in having nearly all of it to play with. Years ago, some anatomists made accurate measurements of hundreds of bones and made up formulae for each one – so that, now, we can get an estimate of the owner's size from any limb bone.'

Powell nodded as Mitchell settled back to his jigsaw.

‘Naturally, the more bones there are available, the more accurate we can be – by taking the average of a lot of calculations.'

Meadows looked curiously at the anatomist as he carefully spaced out each bone from its neighbour.

‘I see – he's allowing for the soft tissue that's rotted away.'

‘That's it. Each intervertebral disc – the things that “slip” in your back – is about a quarter of an inch thick. So he's spacing the bones that far apart.'

Mitchell came slowly upright again, holding his own back with one hand. ‘I think I've dislocated one of mine in the process. I'm getting too old for this stooping game. It's worse than weeding the garden.'

‘Let's have a go. You've done it all except the legs.'

The professor knelt on the edge of the sheet and finished off the lower limbs. He placed the long leg bones in position, including the one that the small boy had found.

The anatomy lecturer looked thoughtfully at the finished job for a moment, then nodded his approval.

‘Right, Leighton, let's run the tape over her. Will you hold one end level with the top of the skull?'

They held a metal rule over the skeleton and read off the length.

‘About five foot four, I make it,' said Mitchell. ‘Dead on, eh? That's what the calculations said.'

Powell grinned, his pink face boyish in spite of his middle age and morbid profession. ‘Be damned queer if it wasn't, Tom. Guessing the height of a complete body is as easy as stealing a blind man's stick.'

‘I can get my photographer up now, can I?' asked Meadows. ‘He should be down in the entrance with his stuff.'

The police photographer duly arrived, loaded down with bags and a massive tripod. While the skeleton was being put on film, the other three went over to Mitchell's littered desk to look at some other photographs that Powell had brought with him.

‘These were taken yesterday with a low-powered microscope,' he explained. ‘They show the saw cuts on the arm bone in close-up.'

The glossy prints were passed between the men. They showed the surface of the humerus of the skeleton, with the area of attempted amputation greatly magnified.

‘The main one goes about halfway through the bone,' explained Powell. ‘And, just below it, there is a smaller slot which I presume was a false start before the main cut.'

Meadows studied the picture magnified the most.

‘You can see the scratches from the saw teeth on the walls of the slot in this one,' he commented.

‘Yes, they seem very close together,' agreed Mitchell.

‘What about this false start – any special significance in that, Professor?' asked Meadows.

‘No, I don't think so – just a failure to hold the saw in the first cut tightly enough. Once it slipped out, the soft tissues would obscure the hole and stop him putting the saw blade back in the same place.'

‘The blade seems to be about a sixteenth of an inch wide – what sort of tool would that be, I wonder?'

Meadows looked at his own print closely. He felt more at home talking about saw blades than about bare bones. ‘Yes, I noticed this on the bone itself,' he said. ‘It could well be a hacksaw with fine teeth like this.'

Powell agreed with the inspector. ‘I think that's very likely, though it's a bit thicker than the little hacksaws I'm accustomed to using.'

‘You can get many different types, sir; we see them in our burglary cases. The type of cut depends on the number and spread of the teeth, as well as the thickness of the blade.'

The photographer finished taking his pictures and came across the room to ask if there were any more to be done.

Mitchell looked at the pathologist questioningly. ‘What about the skull? Shall we have a couple of that for a go at superimposition, if the opportunity ever arises?'

Powell agreed again. ‘We can have a picture of that hole in the skull and the teeth at the same time.'

‘What about that hole, sir – any ideas on what it means?' asked Meadows.

Powell looked dubious. ‘I'll never be able to get up in court and say that it was caused before death. It could just as easily have happened when the roof fell in on her.'

The pictures were taken and the photographer struggled away with his apparatus.

‘That's about all I can do for you now, I think,' said Dr Mitchell. ‘I'll pack this lady up in a box for you to take away.'

To save tedious rearrangement in the future, he slid the vertebrae onto a length of rubber gas-tubing and secured each end with a safety pin. The big bones he put in separate plastic bags; and the hands and feet also had a bag apiece.

After thanking the anatomist for his help, Powell and Meadows carried their trophies of the chase downstairs. They drove in Meadows' car across the college grounds to the pathology institute, which held the Department of Forensic Medicine.

Here, in Powell's room, they dumped the bones and concentrated on something else.

The professor unlocked a drawer in his desk and took out two small polythene envelopes.

‘Here's some of the hair that was found,' he explained. ‘This lot here is as it was found, and the other has been cleaned. I've had them in my possession all the time, just for the record of continuity of evidence. I'm handing them back to you now. All right? We don't want some smart alec of a defence counsel taking the mickey out of us if it ever gets to court – which God forbid!'

Meadows held up the two transparent packets to the window. He studied them with interest. The liaison officer was a careful man, whose long experience was made all the more valuable by a great deal of common sense and quiet enthusiasm for his job.

‘There's certainly a marked difference in the colour of the two samples. What did you do to this one?' He held up the bag of cleaned hair.

‘Just got rid of the years accumulation of mud and slime,' replied Powell. ‘I washed them in an alcohol-ether mixture, and they came up like new – as the TV detergent adverts say! I've got a couple of strands mounted on a slide, if you'd like to see them.'

He went to a bench and switched on the lamp of a binocular microscope which stood there. He fiddled with the controls for a moment before beckoning to Meadows.

‘There, have a look at that. A nice auburn colour, though you can see the true tint better in the hand. I always feel that the microscope makes hair look blonder than it really is.'

As with hacksaws, Meadows felt more at home with hairs than with bones. Fibres of all sorts were frequently sent to the forensic laboratory, being common clues after crimes of violence and robberies. He studied the golden- red strands for a moment.

‘No doubt about this being human, I suppose?'

‘Looks all right to me,' answered the professor. ‘The size, cortex and scale pattern are all OK. One odd thing, though. There are no roots at all. Nor remains of hair bulbs.'

‘What does that mean?'

‘Every end that I've seen has been either a frayed or cut one. Many of the hairs are cut at both ends – so it looks as if the hair was severed from the scalp before burial.'

Meadows looked puzzled. ‘That's more than a bit odd, eh?'

‘I don't know. If the killer went so far as to try to cut an arm off, he might have thought of removing the hair as well, to make identification more difficult. Though why he should have put it back with the body is beyond me.'

‘Is it cut at the scalp, do you think, or just anywhere?' Powell waved one of the plastic bags at Meadows.

‘Some of this hair is a good eight inches long, so I'd think it was almost the full length. As far as I can remember, women used to have fairly short hair styles in the twenties and early thirties. Didn't they call it “bobbed” or something?'

‘What about the roots in the scalp? Wouldn't they survive if the actual hair did?'

‘Oh, it would be impossible to find the roots once the flesh of the scalp disintegrated. They would be a tiny fraction of an inch long and would vanish in all that muck and rubble around the body.'

Meadows collected the packets of hair and prepared to leave.

‘So we're definitely looking for a red-haired woman, five foot four in height, between twenty-two and thirty years of age, sir?' He asked this as he was going through the door of the professor's room into the corridor.

Powell walked slowly with him to the lift. ‘Yes, I think that's a fair description. As near as we can get it without being misleadingly accurate, anyway.'

‘How can you be so definite about the age range, just from looking at the bones?'

‘Well, a person grows by adding calcium compounds – chalky stuff – along a line of gristle, called the “epiphysis”, which lies near the ends of the bones. When the bone reaches its maximum size and stops growing, this line vanishes. We call this the “fusion” time. Each particular bone in the body has its own set time for fusion, which is fairly constant, within a year or two. For example, the lower end of that bone the boy found would fuse at eighteen, give or take a year each way. The last ones to go are at about twenty-two to twenty-five years, usually the earlier age in women. We X-rayed all the bones in this case – that's the best way to see the epiphyses – and found that they had all fused, so that she must be at least twenty-two. In kids, we can tell the age almost exactly. But, as age increases, it gets harder and harder.'

Meadows was still full of curiosity. ‘Why do you put the upper age at thirty?'

‘That's a bit less definite, I admit. But, as a rule, the plates of bone forming the skullcap begin to fuse at about that age, starting on the inside first. There was no sign of this in “Flossie” here, so obviously she is less than thirty. Another thing is the fusion of the spheno-occipital joint.'

Meadows looked blankly at Powell and the doctor grinned.

‘That's just a fancy name for one of the fusion lines in the floor of the skull. It seizes up at about twenty-five, and this girl's is just in the process of doing that.'

‘So she's twenty-five,' suggested Meadows.

‘Ah, these things are a bit chancy – a few years either way has to be allowed. It's the sum total of a lot of facts that adds up to the most probable age. She's got changes in other sutures in her skull, and in the front joint of her pelvis, which suggests that she is in the middle twenties. But, in all honesty, I can't be more definite than twenty-two to thirty.'

The pair halted outside the lift and the professor thumbed the call button for the policeman.

‘I know you keep calling it “she”, sir; is that a dead certainty, or another strong probability, like the age?'

Powell laughed. ‘You're a regular doubting Thomas, Inspector. No, as far as the sex goes, I'll stick my neck out all the way. The chances of saying whether a collection of bones is male or female increases proportionately to the number of bones available for examination. When, as in this case, the whole skeleton is present, the chances reach a hundred per cent.'

‘What's so different in the bones, then?'

‘Oh, the general appearance to start with. The woman's are lighter and smoother; they haven't got the strong ridges where a man's bigger muscles are attached, for one thing. Then again, the pelvic bones are different; the female's are flatter and more open – connected with childbirth, I suppose. There are umpteen other differences, too. The eye sockets are square in the man, round in the woman. The pelvis is the main thing to go for, but all the bones have some sex difference.'

The lift appeared. Meadows, having had his fill of technicalities, left the pathologist to carry on with the day's bag of post-mortem examinations for the local coroner.