A Mexican has pleaded guilty in Brooklyn to working for the family business — an international sex trafficking ring that goes back generations

Angel Cortez Granados, 25, admitted that he wooed a woman and brought her to the United States as his “girlfriend” only to enslave her as a Queens prostitute traveling from client to client in a livery cab. “I threatened her, telling her that she was alone in this country, that nobody would help her, so that she would work as a prostitute,” Granados told Federal Judge Cheryl Pollak. He said that he warned the victim, identified only as Esperanza, that he would call the police if she didn’t follow orders. “Since she didn’t have any papers, (I was) scaring her with the possibility of going to jail,” he said. Six other members of the Los Granados ring have been charged in New York, said Assistant U.S. Attorney Pamela Chen. The feds identified their first victim in 1998. Prosecutors believe that at least 20 relatives are involved in luring women into sexual slavery in New York City. Mexican authorities have arrested four members and at least four others are reportedly on the run. There’s a $78,000 reward. The Granados are from Tenancingo, in Tlaxcala state — notorious as the center of Mexican sex trafficking. The town of 10,000 even holds a procession every year for a “patron saint of pimps,” prosecutors said. It’s also famous for luxurious mansions paid for by the prostitutes’ earnings, called calcuilchil or “houses of ass” in the region’s indigenous language. Chen said that the pimps rope in the women “with some sort of romantic relationship.” But once they get to the United States, they are forced to sell sex, usually for $35 for a 15-minute session. “They use all sorts of intimidation, threats, against the women,” Chen said. “It’s a whole industry, which is upsetting.” The feds have found at least 15 women trafficked by the Granados family ring in the city, Chen said. The pimps often partner with livery drivers based out of Roosevelt Avenue in Jackson Heights, Queens, where promoters hand out cards and even bottle openers advertising sexy girls for “delivery,” she said. Granados, who was arrested by Immigration and Customs Enforcement agents in the Bronx in September 2011, faces a minimum of 15 years in prison and a fine of up to $250,000. He sneaked over the Arizona border with Esperanza in 2010, pushing her into prostitution in North Carolina before bringing her to New York City in January 2011, court papers say. He took most of her earnings — but must now pay her restitution.