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Police Agencies Use Bitemarks as Sources of DNA for Identification Rather than Comparison with Toothmarks

By Dr. David Averill and Dr. Michael Bowers

Sidestepping the years long controversies of bitemark comparison, police investigators have redirected their approach to answer perpetrator identification. Using the bitemark as a source of salivary DNA, the comparison is accomplished using proven biological methods of DNA profiling. These following cases below illustrate the shift to best practice police methods.

Big Sky man arrested, accused of raping 17-year-old
http://www.kxlf.com/news/big-sky-man-arrested-for-raping-17-year-old/

Zion woman denies Gurnee Mills robbery, attack
http://www.dailyherald.com/article/20110825/news/708259526/photos/AR/

Cop impersonator guilty of attempted murder
http://www.compasscayman.com/caycompass/2011/08/25/Cop-impersonator-guilty-of-attempted-murder/

Man gets 22 years in bike path rape
http://abclocal.go.com/wls/story?section=news/local&id=8306284

Burglar helps him/herself to the fridge
http://www.westseattleherald.com/2011/09/26/police-blotter/police-blotter-week-9-26-11

Detective Arrested & Charged with 1986 Murder
http://cmm.lefora.com/2010/02/16/sherri-rae-rasmussen-ruetten-stephanie-ilene-lazar/

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Crime Solved with Key Salivary DNA Evidence Recovered from Bitemark

An arrest was recently made in Boston in conjunction with a 2004 unsolved rape case using DNA recovered from a bitemark. DNA evidence recovered from a bitemark went unmatched until a recently convicted felon who underwent post conviction mandated DNA sampling entered the DNA database. The felon’s DNA profile compared positively to the DNA left on the victim linking him to the crime 7 years later.

Recognizing and documenting the bitemark was critical in this case. In the act of biting, saliva was deposited onto the skin containing DNA, which was recovered by swabbing the area of the bitemark. DNA comparison has become the gold standard in which to identify an individual. One of the early promoters of using the DNA technique in bitemarks rather than matching tooth marks which have had dubious results is Dr. Michael Bowers. Dr. David Sweet in his laboratory in British Columbia is one of the pioneer researchers to isolate salivary DNA from the skin.

In another Boston bitemark case in 1998, a homicide occurred where a bitemark was found on the victim’s body. The initial suspect was arrested based on a forensic dental opinion that his dentition matched the tooth marks left on the victim’s body. When the DNA results came back from the lab the police realized that they had arrested the wrong person. This mistake resulted in a cascade of errors including the dentist being sued by the wrongfully arrested individual, the real perpetrator remaining free, and embarrassment by the authorities. It is fortunate in this case that there was DNA to prove that the initial suspect was innocent. Otherwise, he may very well have ended up wrongfully convicted spending his life in prison. This is because the forensic dentist that made the error is the most experienced and skilled bitemark analyst in the world. With his world famous notoriety he would have been impossible to oppose in court even though there is no tested science behind his bitemark analysis opinion.