By December 1990 , the inquiry team decided they had sufficient circumstantial evidence to convince the Crown that there was a reasonable prospect of securing convictions against Black .
Clark was worried that the inquiry had not uncovered any forensic evidence to tie Black to the murders .
By December 1990 , the inquiry team decided they had sufficient circumstantial evidence to convince the Crown that there was a reasonable prospect of securing convictions against Black , although Clark was worried that the inquiry had not uncovered any forensic evidence to tie Black to the murders .