Crime Library: Criminal Minds and Methods

Bite Marks as Evidence to Convict

The First Bite

Linda Peacock was missing. She was a fifteen-year-old schoolgirl from Biggar, Scotland, near Edinburgh, and she had not come home. Officials searched all night before they discovered her body in the local cemetery. She had been strangled and beaten, and her bra and blouse were in disarray. On her right breast was an odd bruise.

It was 1967 and bite marks had not yet been used definitely in court for identification of a perpetrator. This case was to set an important precedent and pave the way for such evidence to be used in other cases of rape, assault, and murder.

Since the bruise appeared to have been made in the struggle, numerous photographs were taken of it. Analysis indicated that whoever had killed the girl had bitten her hard on that spot. They brought in an expert, Dr. Warren Harvey, an odontologist, and he confirmed that this mark was indeed a bruise. A closer look at it indicated that there was some unevenness to the killer's teeth, which could make identification easier. To the dentist, it appeared that the man had jagged teeth.

It seems that there were also witnesses to the crime. A male and female were seen at the cemetery gates the night before, and the girl who was described appeared to match the description of the deceased. From the way they spoke, the girl had seemed to know the man she was talking with. The same woman who told this tale said that she had seen them around ten o'clock in the evening and about twenty minutes later, she had heard a girl screaming.

A systematic search was undertaken to try to eliminate townspeople, and then police went to a detention center for young males, where nearly thirty of the inmates were asked to provide dental impressions of their teeth to compare to the well-defined bruise. Dr. Harvey studied them all and narrowed the suspects to five. Each was asked for another impression. At this point, Keith Simpson, a pathologist with thirty years of experience, joined the team. Together these men studied all the impressions and came up with a single suspect: seventeen-year-old Gordon Hay.

Hay had been brought in for breaking into a factory and he proved to have a serious problem with authority. However, he submitted to yet one more dental impression procedure, which showed that one of his teeth was pitted in two places by a disorder known as hypocalcination. The pits matched the impressions made on the victim's breast. That meant they could take it into court with confidence, even though such evidence had never before been utilized as the defining piece of physical evidence.

As part of his presentation, Harvey made an examination of the teeth of 342 young men who were soldiers. Only two had pits of any kind, and none had the two pits that shaped Hay's teeth. From his analysis, he concluded that Hay's teeth were so unique that it would be virtually impossible to find another set of teeth like his that could come as close to the bruise impression.

At his 1968 trial, Hay claimed that he was in the dormitory at the detention center at the time of the girl's death, so he could not be the person they were looking for. However, another inmate claimed that Hay had actually come in later than he told the court and there was mud on his clothes. Another boy claimed that Hay had met Linda Peacock at a fair just before she was murdered, and he had told some of them that he planned to have sex with her.

To clinch it, the prosecution introduced the dental evidence. Since it was so unique, the defense put up a fight. They wanted this evidence to be ruled inadmissible. When the judge allowed it, they brought in their own dental expert to refute it, or at least to confuse the jury with dueling experts. The jury apparently bought the evidence because Hay was convicted of murder.

Still, the defense did not give up. They appealed, arguing once again against the bite-mark evidence. However, the court upheld the judgment, which meant that other cases could now introduce bite-mark testimony.

Bite-mark evidence also became part of the technique of profiling unknown criminal assailants, because the presence of a bite mark indicated certain psychological factors. Profilers provided some of the best information about the motivation for biting during an assault.

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