The task force investigated earlier sexual crimes from 1985 to 1987 with similar modus operandi, but could not locate some witness statements and crime scene exhibits, including a tape used to tie up a victim and also a rope used to tie a victim.[1][2] The head of the Spectrum Task Force, David Sprague, said that some exhibits hadn't ever been examined by forensics, and had either been lost or thrown out.[17] The police established a Rape Squad in April 1989, with nine detectives dedicated to investigating serial rapists throughout Victoria, particularly in Melbourne.[20] The police established the unit after a review into the effectiveness of their rape investigations, by the Rape Investigation and Evaluation Group, found they needed a more coordinated and professional approach to investigations.[20][21]