For everyone saying to call the police. That will not do anything. The only way the police will intervene right off the bat is if regular physical abuse occurs or if the living conditions are not suitable for children. I.e no power, water, heating, mold, food, dirty clothes/trash everywhere, ex.
The best way for authoritative action would be to, as stated, contact child services. They would perform an investigation and would contact the police with viable evidence enough for an incarceration or forced separation.