To me, the meaning is very fuzzy. As far as I am concerned it just means that these folks were living in Nashua and tells me nothing about their citizenship or immigration status. I see these types of reports using very similar language all the time and it often turns out the criminals are also illegals. The media hates to include that detail so they omit it or give us some fuzzy language that implies they are citizens. They could have said Brazilians and that would have been equally fuzzy but implied the opposite as they could in fact be Brazilians living here as legal immigrants or naturalized citizens. Unless they actually say so, we can't know and can only speculate. My speculation was based on the statistical fact that illegal immigrants are far more likely to be involved in criminal activity, and particularly immigration related criminal activity, then citizens.