There are some dog bite cases in which the identity of the dog cannot be accurately determined. This could happen because the victim is unable to accurately identify the dog, or because the dog left the scene after the attack happened. Identifying the dog involved in an incident also becomes problematic if the owner of the dog claims that their dog could not have possibly been involved.
When uncertainty exists, certain information needs to be collected, if feasible, to rule out a suspect dog. This obviously assumes that the injuries to the victim were caused by a dog, and not by some other animal, or by some other means. Occasionally relevant forensic information may be ignored, for reasons which may stem from the fact that investigators are ignorant of what needs to be preserved or collected in a suspected dog bite case, or because an incident doesn’t come to the attention of authorities until well after the attack happened, hence information is lost. Nonetheless, in criminal cases, if the relevant forensic information is not collected, this might compromise the ability to prosecute a dog owner.
Collection of forensic evidence necessitates access to the suspect dog, preferably as soon after the incident as possible in order to determine if there was any transference of meaningful information from the victim to the dog or vice versa. This might include blood, hair, or clothing fiber from the victim transferred to the dog’s coat. Likewise, the victim needs to be examined to determine if blood from the dog, hair or its saliva is on the victim. Measurement of the distance between the dog’s upper canine teeth can also be made to determine if they approximately align with puncture wounds on the victim’s body.
The collection of forensic evidence aims to connect or match evidence between the dog and victim. Evidence like this is non-circumstantial and differs from evidence such as an evaluation of the dog’s temperament and the likelihood that the dog would attack a human. Determining if a match exists between physical evidence is highly accurate through the application of DNA analysis. The interested reader should consult the publication of Bruner, et. al. for amplification of the techniques involved in this pursuit (Bruner, J. et. al. DNA profiling of trace evidence – mitigating evidence in a dog biting case. J. Forensic Science, 2001, 46, 1232-1234).