I can't find in which thread we mentioned the case of a bunch of new Chinese immigrants who immediately signed on for welfare payments after arriving in Osaka. It took place around the same time as the fuss about child allowance payments was coming to a head. Here's Japan Probe's mention of the case or this Japan Times article if you want to refresh your memory.
Anyway, the press is now reporting that police have conducted DNA tests and determined that at least two are not related as they have claimed. Jiji Press (Japanese) mentions that two claiming to be mother and daughter are now suspected of making false statements in violation of immigration laws.
This did seem like a remarkable scam attempt of the kind to confirm all local fears of Chinese welfare scroungers. It's somewhat surprising, however, that the police have resorted to DNA testing to break this case given that the techniques are still not widely used even in serious crimes cases.