PLANO, Texas (CBSDFW.COM) — A federal grand jury indicted a Plano couple in a widespread sex trafficking ring this week.

Authorities say Quan To and Li Xin operated a prostitution enterprise out of a Richardson condo, a Plano house and a commercial foot spa in Garland. The couple allegedly lured Asian women to North Texas — often with the promise of legitimate masseuse jobs — and then coerced them into prostitution for financial gain.

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A task force of state and federal law enforcement agencies conducted an 8-month undercover investigation, ending with the couple’s arrest last month. They say the investigation began because citizens noticed “suspicious behavior” and reported it.

United States Attorney Joseph D. Brown said this type of case results when there’s a gross disparity in power between the person who is trafficking the worker and the women themselves.

“We have alleged — and we believe that the evidence will show — that these women were coerced into their activity through intimidation, through financial manipulation or other means,” Brown said.

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Richardson Police Captain Gary Tittle said they will not stand for this type of behavior in the community.

“We will fight the criminal element, and we will be successful at the end of the day,” Tittle said.

Eight women were recovered in the sting, but investigators believe there are more victims.

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If convicted, To and Xin could face up to life in federal prison.