Human Remains Detection K-9's or cadaver dogs are specially trained to "alert" to the odor of decomposing human tissue, and then follow that scent to the source of the odor where they perform a trained indication.  These dogs are particularly useful in locating clandestine graves and disarticulated body parts.  They may also be utilized to search buildings and vehicles for trace amounts of tissue and blood.  HRD K-9's must be trained on all types of tissue from bone to organ to blood, and a variety of sample sizes and states of decompsition.