Six people have been sentenced in U.S. District Court in Seattle for their roles in an organized prostitution crime ring, including using apartments or hotels in Kent, Bellevue, Kirkland, Lynnwood, Olympia, Lacey, Puyallup, Renton, Tukwila, Federal Way and Seattle.

The leader of the ring, Fang Wang, 29, of Queens, N.Y., was sentenced last month to 30 months in prison. At her sentencing hearing, U.S. District Judge Thomas S. Zilly said the “nature of the offense is very troubling to the court,” according to a U.S. Attorney’s Office news release on Thursday.

Yongguang Wu, 28, of Seattle and Steven Thompson, 59, of Renton, were each sentenced to eight months in prison. Yunzhong Chen, 45, and Yaoan He, 33, of Seattle, were each sentenced to one year in prison. Zhaofeng Zhang, 23, of Seattle, was sentenced Thursday to 21 months in prison. Zhang continued to post advertisements, rent apartments and connect customers with ringleader Wang even after being contacted by law enforcement.

According to records in the case, federal and local law enforcement partners worked jointly to investigate a criminal ring making hundreds of thousands of dollars through the prostitution of Asian sex workers. In partnership with the FBI, the King County Sheriff’s Office and police departments in Bellevue, Redmond, Renton, Seattle and Tukwila identified numerous brothel locations through their analysis of backpage.com, cellphone and other business records.

The joint team of local and federal investigators then conducted surveillance of the ring’s activities. Law enforcement determined that multiple locations were linked to the organization via ads placed with websites such as backpage.com. The investigation revealed that the same internet protocol addresses were used for placing many of the ads, and phone numbers associated with the ads were linked as well – in some instances to call centers located in New York and Washington, D.C. In other cases, the law enforcement agencies followed up on citizen complaints about apartments being operated as prostitution locations and confirmed that the organization was in fact conducting prostitution in those locations.

The investigation revealed that Wang – the apparent leader of the operation – spent approximately $100,000 to increase the traffic to her ads on the backpage.com site. Other defendants played different roles – renting apartments, transporting sex workers to various locations, purchasing supplies, collecting money from the sex workers and placing ads.

Prostitution activities associated with the ring occurred in apartments or hotels in the greater Seattle area. Other locations where the ring operated included Eastern Washington cities such as Richland, Kennewick, Wenatchee and Spokane. The sex workers were frequently moved throughout the area.