Missing Children (World of Forensic Science)
Children can disappear inadvertently or as a result of deliberate abduction, or murder. Typically, an investigation will assume that the child is still alive, and so will be geared to locating the child. While much of this effort involves police work that is not forensically-oriented, forensic science plays an important role.
The nature of the forensic activities can change with the length of time a child is missing. For example, as will be dealt with in more detail subsequently, computerized techniques can alter the photographic image of a child to approximate the child's appearance through adolescence and into adulthood. Such a visual cue can prove valuable in recognizing a children years after they have been reported missing.
Forensic science plays a grimmer role when a child is discovered dead, or when an unidentified body or skeleton that may potentially be the missing child is discovered. In this case the focus naturally shifts from a happy reunion of the child with loved ones, to the identification of the body.
As sad as the latter task may be, this aspect of forensic science can help grieving family members to begin to deal with the reality of what has transpired. Finally, forensic science is invaluable in establishing the cause of death of a missing child, especially when foul play is suspected.
In age progression, a forensic artist uses a facial photograph of the missing child to render an image of how the child might look as a pre-adolescent, adolescent or even an adult.
An image can be created the old-fashioned way, using a pencil and sketchpad. This type of image recreation actually has become quite sophisticated. In the 1950s a facial identification kit was developed that consisted of a series of clear stackable sheets ("foils") that allowed a myriad of different hand-drawn facial features to be laid on top of one another on different-shaped faces. The thousands of possible combinations made it possible to produce a final image that proved to be very similar to a person's true appearance.
Today, computer programs enable the forensic artist to digitally scan the child's image into a program and then digitally manipulate the image to approximate the effects of aging. Forensic age progression is a combination of science and art. It relies on the rendering skill of the artist and knowledge of the development of facial muscles, features such as the eyes and nose, and the change in shape of the skull with age.
Predictably, faces broaden and lengthen during the transition from the childhood years to adolescence. Primary teeth are lost and secondary teeth appear. The bridge of the nose will tend to rise. As the skull expands, the eyes tend to narrow, the mouth becomes wider and the nose lengthens. Hair that is lighter colored tends to darken.
By about the age of 12, the facial features that are present will persist throughout life, unless surgically altered. Some subtle changes can occur; eyebrows can become more extensive and the cheekbones more prominent. However, other changes may occur that may need to be factored into an image. As examples, hairstyles will change, a hairline can recede, and changing optics of the eyes may necessitate the use of glasses.
In an age progressed image that is within a few years of the child at the time she/he went missing, these age-related changes will be kept to a minimum. However, if the child has been missing for an extended number of years, then a series of images can be made, to give a better overall portrayal of the person's possible appearance.
If the missing child has older biological siblings, then their appearance will be scrutinized, as will parental features, since some of their facial features acquired by the siblings from their biological parents will likely have been acquired by the missing child.
Medical records of the missing child can provide useful information in image reconstruction. For example, the presence of a facial scar from a childhood accident, moles, and even tattoos can remain with the child for life, and will be a feature of the age progressed image.
In a related area, image rendering is also done if the missing child is suspected of being abducted and the identity of the kidnapper is unknown. In this case, since the abductor may well try to disguise their appearance, different images may be produced, based on information gleaned from witnesses, surveillance cameras or other means. For example, a man can be shown clean shaven, with various styles of facial hair, and with a face that reflects a weight gain or loss.
Particularly in the case of an abduction of a child by an unknown person, the need for eyewitness information is pressing. Such information can be valuable in producing an image of the suspect, and for trying to piece together the events of the abduction.
Obtaining information from eyewitnesses calls for tact and special skills on the part of the forensic investigator. Eyewitnesses, who themselves may be traumatized by what they have witnessed and whose memory can be subject to manipulation, need to be given the time and emotional encouragement that unlocks accurate recollections of the event.
A forensic investigator will assess the information provided by a witness while considering the person's involvement with the event. For example, the information provided by someone who had only a brief glimpse of the missing child and/or suspect may not be as reliable as the information from someone who had a more prolonged view. As another example, if the eyewitness normally wears glasses but was not at the time, then the quality of the information, while not necessarily suspect, needs to be considered cautiously.
Other forms of eyewitness information are available. Surveillance cameras that are an ever-present facet of daily life can provide a picture of the child and an abductor, for example.
Fingerprints are unique identifiers that are invaluable in the identification of a missing child and, in the case of an abduction, the suspect. For fingerprints to be useful, a child's fingerprints need to be already recorded and on file. Programs such as ID Me Now, sponsored by the Child Protection Education Foundation of America, incorporate on a card high quality images of fingerprint patterns with a digital facial photograph, dental records, contact numbers and personal information, and even information on how to collect a cell sample for deoxyribonucleic acid (DNA) extraction.
Fingerprint patterns can also be submitted to a databank that is administered by the Federal Bureau of Investigation. The fingerprint patterns obtained from a missing child (or recovered corpse) can be compared to the hundreds of thousands of digitized patterns resident in the database to determine an identity match.
Such child fingerprint collection is, however, more the exception than the norm. In this case, a forensic investigator may instead be able to obtain a fingerprint of a missing child from an object known to be handled by the child.
The conclusion of a missing child case can be tragic with the discovery of a corpse or skeleton. Identification of the body or remains as that of the missing child becomes the priority. If an intact skull is found, it can be used to create a three-dimensional reconstruction of the facial appearance of the person. The shape of the skull, combined with knowledge of the typical thickness and arrangement of facial and head muscles and tissue can be used to physically create a face.
For this task, modeling clay is applied to the skull. The clay mimics the muscles and tissues that underlie the skin. The shape of the nose can be deduced from measurements of the nasal aperture; the hole in the skull where the nose once was. Typically, the width of the nasal aperture is increased by five millimeters on either side. Other measurements of the nasal aperture are used to calculate the approximate length of the nose. Appropriate facial hair and prosthetic eyes are inserted, and the reconstruction is photographed. The final image can be very similar to the actual image of the deceased.
Skin, tissue, muscle and even bone that can be recovered can be used as a source of DNA or a related genetic material known as ribonucleic acid (RNA). Through various sophisticated means, the genetic material can be amplified in number, and the sequence of nucleotide building blocks that comprise the DNA or RNA can be determined. These genetic sequences can be as unique to an individual as is a fingerprint pattern. People inherit genetic material from their parents; indeed, this is the basis of paternity testing that is used to establish if a man is the biological father of a child.
The genetic identification utilizes specialized DNA that is known as mitochondrial DNA. The pattern of mitochondrial DNA between mother and child can be identical. This generational similarity of genetic material has been used in El Salvador to identify the remains of children who were abducted and murdered by the Salvadoran military in the 1980s and, more happily, to reunite children who were abducted but not killed, with their biological parents.
SEE ALSO Anthropometry; Autopsy; DNA profiling; Integrated automated fingerprint identification system; International Association for Identification; Mitochondrial DNA typing; Paternity evidence; STR (short tandem repeat) analysis.