One cold February morning the mangled body of a homeless derelict turned up in one of Houston's wooded and desolate suburbs. The body was deteriorated and torn apart by animals.

Animals disturbing bodies was not unusual, however, forensics showed clear and very convincing evidence that one or more animals may have been involved in the killing itself. Perplexed Houston police asked the Health Department's Animal Control Director, Dr. Duncan MacDonell, to assist.

Footprints of the suspect animal showed it to be a large canine, much bigger than any domestic dog. Representatives from Texas Parks and Wildlife speculated that it might have been a very large Mexican red wolf.

Within a week a second body showed up, then a third. It wasn't long before MacDonell began to suspect the killer might be human, and it might be someone he knew.