ROCKVILLE, Md (WJZ)– A sting operation lands three people behind bars, charged with running a prostitution and human trafficking ring in Rockville.

Monique Griego has more on the investigation.

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WJZ talked with several people who worked around some of the businesses. They said everyone suspected something illegal was going on but didn’t know how to stop it.

Police say a modest business complex on Hungerford Drive in Rockville was home to three alleged prostitution and human trafficking operations.

“Definitely wasn’t a shocker to me,” said Todd Cassidy, who works nearby.

Cassidy says it was obvious massage wasn’t all that was going on behind closed doors.

“People were only showing up after normal business hours,” Cassidy said.

In all, Montgomery County Police raided six businesses within just a few miles.

They include the Pink Spa, the Tropical Spa, Executive Body Work, Best Massage and the Ya Ya and Wa Wa Spas.

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“They were running under the guise of being accupressure or massage parlors,” Rebecca Innocenti of the Montgomery County Police Department said.

Investigators arrested four business owners, saying they acted as “pimps.”

“The owners were really targeting a certain type of women who perhaps don’t have ties to the community or need financial help,” Innocenti said.

People who worked around the businesses say there were several things that made them suspicious.

“We’d see the girls all the time in low-cut short skirts, men going in and out,” an area business owner said.

Right next door to one alleged front is a legitimate massage parlor. That owner told WJZ she turned men away who mistakenly came to the wrong shop looking for young girls and sexual favors. She,  along with others, are glad police shut it down.

“It’s great to know that they’re on to that type of activity in the area,” Cassidy said.

Police don’t believe these are the only operations in the area. They’re asking anyone with information on these case to call them.

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The investigation into human trafficking has been made easier thanks to a new exemption in Maryland law allowing wiretaps in such cases.