Nine women were arrested as Harris County Sheriff's deputies raided the three places on 1960 near Red Oak.
Behind the dark-tinted glass, investigators say they found evidence of Houston's dirty little secret. What they know these raids show is that sex trafficking is alive and well.
Shackled and handcuffed, nine women in all were led out under arrest and didn't say a word. Officers busted three businesses in this one strip center. They advertise relaxation and massage when in fact, investigators believe what they really sell is sex.
"Found condoms, dark lit rooms, massage tables that are pushed up against the wall -- homemade massage tables, you know, just out of two by fours. They put a pad down and then they put a towel down on that," said Sgt. T.E. Kiser with the Harris County Sheriff's Office.
The women work at places called Empire, Royal and Crystal; businesses which share a parking lot with a day care and two churches. And it's not the first time they've been surrounded by patrol cars and raided.
Shirley Ratcliff at Hearing Aid Express next door says the questionable activity is obvious.
"They come at all hours of the day. They'll park way over there, drive over here, walk over here. You know what's going on," Ratcliff said.
But after each bust, the shops are back open within days. Officers arrest the women for prostitution, but who they really want are the people who profit.
"We have to peel the layers back, you know? You've got the girls. We have to get past those girls and find out who's bringing them in. They don't want to talk. They're afraid," said Sgt. Kiser.
The women, all of Asian descent, also live on site. Undercover officers say they found showers and beds in dingy back rooms.
"It's a big red flag, huge red flag," said Adam, who didn't want us to use his last name.
Suggesting they are really victims held against their will. Adam works undercover for a Christian non-profit whose mission is to end sex trafficking.
"They're held there against their will. Nobody wants to eat, sleep and work all in the same place, 24 hours a day, 7 days a week," Adam said.
Along with the nine arrests, officers also cited two women for not having their massage therapist licenses. Of them all, only one cooperated. They took her for questioning and they hope she will lead them to the owner, but they say they're skeptical.