John E. Douglas, a former longtime FBI agent and current criminal profiler, said that the murders were more indicative of a single murderer intent on degrading and punishing the victims, than of a trio of "unsophisticated" teenagers. Douglas believed that the perpetrator had a violent history and was familiar with the victims and with local geography. Douglas was formerly FBI Unit Chief for 25 years of the Investigative Support Unit of the National Center for the Analysis of Violent Crime. He stated in his report for Echols's legal team that there was no evidence the murders were linked to satanic rituals and that post-mortem animal predation could explain the alleged knife injuries. He said that the victims had died from a combination of blunt force trauma and drowning, in a crime which he believed was driven by personal cause.