The police must surely know who's behind this. We had one family in this area who were behind pretty well every incidence of this type of crime and, as I understand it, the police hauled them all in for interview every time a crime was committed. Sometimes it worked and the offender was locked away for a good long time, sometimes not, but eventually the rest of the family relocated - not a nice, clean ending to the story but a huge relief locally. The family was a tight-knit bunch and the children were brought up ignorant of any alternative way of life.