Here's how it goes: A group of runners (aka pack of hounds) looks for clues (dashes of flour or chalk marks) on the ground to indicate the correctpath.
Burleigh answered that the Italian police investigating Kercher's murder made mistakes and that heavy media attention after Knox and her ex-boyfriend Raffaele Sollecito, who was also convicted, made it hard for the police to admit their mistakes and put their investigation back on a fair and correctpath.