They will have been rounded up in an attempt to prevent them constructing alibis for those known/suspected of having been involved, and also in destroying evidence.
There is a similar 'community' close to where I live; most of the residents are hard working and law abiding, but a few families are not. They exercise strong intimidation against those who might know of their illegal activities; cars and property vandalised, children and even local councillors bullied, and police harassment claimed the moment they are investigated. Several have been in prison for GBH as well as burglary and fraud but they still continue to exercise a complete contempt for the law, which passes down through their families.
And those children receive a huge amount of support in school, when they are there, if not away 'travelling' because of their 'Romany Heritage.'