Estimating the Early Postmortem Interval in Domestic Canines

The estimation of time of death (TOD) can be used to aid law enforcement officers in solving criminal cases involving a death. By determining the period from the TOD until the time the body is discovered, forensic investigators can potentially link or rule out a suspect. A great amount of research has been conducted for the purpose of establishing a reliable and accurate means of estimating TOD in humans. In contrast, most animal studies have centered on techniques that might be applied to human forensic cases or to aid wildlife officers in prosecuting criminals who violate conservation laws. However, little research has been conducted concerning the estimation of TOD in companion animals, especially canines. Estimating TOD in companion animals can aid investigators in solving animal abuse cases involving the death of a pet and/or the murder of an owner that coincides with the death of the pet.

The objectives of this study are to take selected TOD measures and apply them for the purpose of expanding the current scientific knowledge concerning TOD determination in canines. Such information should be useful in animal cruelty/abuse investigations by providing a practical and inexpensive quantitative methodology of estimating TOD, maximize the probability that investigators with limited experience will collect useful data, and aid in teaching animal cruelty/abuse investigators proper forensic techniques for handling and collecting data in the field. The measures chosen for this study include postmortem temperature declines in the brain, liver, rectum, and external ear canal and analysis of changes in the concentration of vitreous humor potassium after death. Recording data for these measures are relatively easy, inexpensive, and have been shown in many studies to be the least controversial and most accurate means for estimating TOD. This study documented that body temperature declines measured in the rectum, liver, brain, and external ear canal can be documented using relatively inexpensive and readily available instruments. Further, this study confirms the work of others that changes in K+ concentration in the vitreous humor of the eye is a reliable measure for use in estimation of TOD in dogs.

Keywords: Estimation of time of death; Forensics; Canines; Core body temperature; Vitreous humor; Potassium