The city of Kent has shut down 18 illegal massage businesses that were not in compliance with Washington state health standards.

KING-TV reported that city authorities have confirmed the illicit businesses operated late at night and were often fronts for organized crime.

City officials say there was a high level of concern the businesses were part of an international human trafficking scheme. Authorities say Kent Police Department officers began investigating in 2018 and found 18 storefronts.

City officials say a recently passed city ordinance makes it easier for police to make arrests after determining if businesses are in compliance with state health requirements.