detectives investigating the disappearance of three-year-old william tyrrell believe he may have been abducted by a paedophile ring when he disappeared from his grandmother 's house last september .
he said detectives from the homicide squad and the sex crime squad are ` vigorously perusing that line of inquiry and this investigation is moving at a very fast pace .
' ` we are perusing every lead that we get , ' detective willing said .
the news comes as the parents of the missing toddler have begged for his return in a paedophile ring .