CHICAGO (CBS) — A massage parlor owner was convicted Monday of trafficking foreign women, in some cases to work as prostitutes for him.

Alex Campbell, 45, also called “Dave” and “Daddy,” was convicted of federal counts of sex trafficking, forced labor, harboring illegal aliens, confiscating passports and extortion. He admitted to abusing forcing four foreign women to work for him, and abusing them physically and mentally, for a year and a half starting in July 2008.

Campbell had operated Day and Night Spa on Northwest Highway in Mount Prospect, and the U.S. Attorney’s office says he had three women from the Ukraine and one from Belarus working for him as virtual slaves.

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The victims all testified as prosecution witnesses during the trial. Co-defendant Danielle “Princess” John, 25, who pleaded guilty before trial to two counts of harboring illegal aliens, and decided to cooperate with prosecutors.

In court, the testimony showed that Campbell recruited and groomed foreign women with no legal status in the United States to join his “Family,” which he claimed would provide them with jobs in his massage parlor, a place to live, and assistance with immigration. But once he gained the women’s trust, he “branded” them with horseshoe tattoos and took away their passports and visas.

The women had to work long hours for Campbell, and he beat and punished them if they disobeyed, prosecutors said.

In one instance, a victim told federal agents she paid Campbell $10,000 after he promised he’d help her. After that, he demanded sex from her and forced her to have sex with another woman while he videotaped it, according to charges unsealed in January.

Campbell then allegedly upped his demand of money and told her he’d broadcast the footage if she didn’t pay up, according to the charges.

Campbell also allegedly admitted to being a pimp when he was arrested by Chicago Police during a prostitution investigation, the Chicago Tribune reported in 2010.

He operated the Day and Night Spa “cleanly” without any prostitution going on to avoid problems with law enforcement, but forced one victim to engage in prostitution with customers at other massage parlors, prosecutors said.

An earlier trial against Campbell ended in a mistrial last summer, after one of the masseuses, Ukrainian immigrant Liudmyla Ksenych, recognized Campbell defense attorney Douglas Rathe as one of her customers as she testified for prosecutors, according to a Chicago Sun-Times report.

Rathe admitted that he had given Ksenych perfume and sent her e-mails, the newspaper reported. He said although it was a “stupid” thing to do for a married man, he only ever went for massages and never got the sexual “extras” that some women testified they had been instructed to perform, the Sun-Times reported.

This time, a jury convicted Campbell in two to three hours

Campbell now faces a minimum sentence of 15 years in prison on the sex trafficking count alone, and a maximum of life.