Feature

Forensic Reconstruction

Reconstructing the face of a dead person forensically could help in establishing their identity, but the technique is not without its problems.

By Jonathan Christiansen

In May 1990, two people walking their dogs stumbled on the decomposed body of a man, lying near a stream off Cove Rd between Waipu and Mangawhai Heads, near Whangarei. Although police launched a homicide investigation, they were unable to identify the man, and over 500 people listed as missing were slowly eliminated from the enquiry.

There were no clues as to the Waipu Cove man's identity. Details of clothing, age and physical size brought no identification, even though they were given wide media coverage.

Police had all but given up the case when I expressed an interest in using reconstruction techniques to produce a reasonable facsimile of what the man may have looked like in life.

This case was the first use of forensic reconstruction in an ongoing attempt at establishing a person's identity in New Zealand. There have been very few attempts at facial reconstruction in this country, and most have been used as an aid to confirm identity.

The first such reconstruction was in 1981, carried out by Dr Tim Koelmeyer, of the Auckland School of Medicine, on a skeleton discovered in sand dunes.

In this case, the technique was used to confirm identity, and only one side of the face was reconstructed. As a further development, video superimposition was used, comparing photographs of the dead man and x-rays of the skull with the reconstruction. A surprisingly accurate match was obtained.

Superimposition of a reconstruction and photographs of the deceased was also used by Koelmeyer in confirming the identity of a skeleton found at the Waikumete cemetery in 1982.

In each case, however, a wealth of other clues had led to an identification, with the reconstruction providing confirmatory evidence. The Waipu Cove case offered no such evidence.

The technique of physically reconstructing a face has evolved over the last 100 years. Investigators in the late nineteenth century used sooty needles and cadavers to determine the thickness of facial tissues at specific locations on the face.

Three dimensional reconstruction was pioneered by scientists, such as Russian Mikhail Gerasimov, around the turn of the century. He claimed to have identified Ivan the Terrible and several other famous figures, and became known as the "Face Maker of Russia".

The technique has now been widely used, with leading American forensic sculptors Betty Gatliff and Clyde Snow completing over 70 reconstructions.

Art And Science

Reconstruction work involves both some artistic ability and a background knowledge of anatomy. Anatomical data on the thicknesses of facial tissues at various points is vital in carrying out an accurate reconstruction. Forensic anthropology texts contain such data tables. For example, the average tissue thickness in a male Caucasian over the horizontal ramus of the mandible is 17.53 mm.

The Waipu Cove Man illustrates the basic techniques of forensic reconstruction. Observation is the first stage. Time is spent examining the skull for unusual or distinctive features.

The Waipu Cove Man had a markedly protruding lower jaw and a jaw shape indicative of European origin. There were few teeth remaining -- an upper molar and four teeth in the jaw. The remnants of the nasal bone indicated a past break, with deviation to the left. The remnants of the scalp indicated that he was close to bald.

The second stage was to sketch a possible likeness. This was done by first sketching the skull in life size and then overlaying tissues at the correct depths, removing the original sketch of the skull. These sketches were aged, and bore a surprisingly close resemblance to two previous sketching attempts.

Building A Face

The actual reconstruction itself closely followed standard methods. The materials I used were ordinary potter's clay, which allowed long-term malleability, and plasticene. The latter was cut into small, pencil-shaped cylinders of specific lengths which, when placed on the skull, gave an accurate guide to tissue depths.

The clay was then applied directly to the skull, following muscle groups and anatomical tissue layers. I began with the frontalis and temporalis muscles, gradually building up a complete facial musculature.

I used an eyeball size of 24 mm (normal range is 22 -- 26 mm), and careful attention was paid to the positioning of the eyeball in the socket.

Some features required more artistic imagination than strict science. The nose is a particular problem, with the length roughly proportional to the nasal spine and the width roughly equal to the spacing between the eye-teeth.

However, in the Waipu Cove case, neither of these approximations could be made, due to the lack of teeth and the distortion of the nasal spine.

The mouth must take into account the teeth and the bony architecture, though the thickness of the lips is often guesswork. This is also the case with the ear. An average size is used, with the top of the ear aligning with the eyebrows.

Finishing touches included the aging, which was the most difficult aspect, as the man was around 60. The problem here was making the man look old enough, but not too old. The hair and eyebrows were added, again using the clay. There was no attempt to colour the reconstruction, as this could have been misleading, and I wanted those viewing the face to concentrate on shapes, not details.

Is It Useful?

Facial reconstruction has resulted in identification success rates as high as 75%, although these "success" rates do not take into account whether other information provided important leads or not. General opinion is that this technique is of relatively limited usage.

The principal problem is that very small changes to facial detail can render a person unrecognisable -- the reason why disguises work.

Too much of the anatomy is not reflected by the bony architecture, and although several reliable empirical methods can be used, there is still a great deal of guesswork. This has led several authors to use the term "forensic approximation", rather than reconstruction.

The Waipu Cove Man reconstruction was shown to a very large media audience, with no result. There were, however, numerous replies with names of possible missing persons.

It appears that although these methods may be very subjective, and may not in fact resemble the deceased, they do stimulate the public to report previously unreported missing persons.

Jonathan Christiansen is a 5th-year medical student who has been working in the Department of Forensic Pathology at the Auckland School of Medicine.