Supporting the Police

Dog DNA forensic science in action

Case Study 1: Reuniting Half-pint

After a litter of eight chihuahua puppies was stolen from a breeder, Cellmark was called in by the police to help investigate.  Intelligence led the police to a woman who lived in the area who had recently acquired a chihuahua puppy which she had called Half-pint.  The owner of the stolen puppies identified Half-pint from its markings as one of the 8 stolen dogs but both the woman and her partner denied any knowledge of the burglary.  The woman told the police that she had bought Half-pint from an unknown man in a van for £300 and had paid in cash.

The police sent Cellmark mouth swabs from Half-pint and also from the putative parents, the breeder’s male chihuahua Jason and the breeding dam Kylie.  Canine STR profiling was carried out and all the components in the 18 DNA markers found in Half-pint’s DNA profile matched marker components in either the profile of Jason or Kylie providing strong evidential support that they were Half-pint’s parents.

As a result Half-pint was returned to the breeder, the rightful owner.

Case Study 2: Prosecution for injuring a dog

Following an altercation between a man and his girlfriend it was alleged that the man stabbed the girlfriend’s dog Cagney multiple times causing serious injuries.  During the incident the man also stabbed himself in the foot.  Cagney survived the attack and her injuries were subsequently treated by a vet and she made a good physical recovery. 

The police brought this case to Cellmark after the man denied injuring the dog.  Cellmark was provided with the suspect’s blood-stained clothing and footwear to determine if any of the blood present on this clothing could have originated from Cagney.  The case was complicated by the fact that some of the blood was likely to have originated from the suspect, since he had injured himself during the alleged attack, and some of the blood staining was likely to be a mixture of human and animal blood.

The clothing and footwear were first examined and tested with an immunological test which is specific for human blood – it does not produce a positive result with canine blood.  This allowed our scientists to identify and sample the non-human blood staining.  Canine STR profiling was carried out on a stain recovered from one of the shoes and compared to a mouth swab taken from Cagney.  The profiles matched, providing strong evidential support that the blood on the suspect’s shoe originated from Cagney.

The dog DNA profiling results in this case provided scientific evidence to allow the police to prosecute the suspect.