BEIJING — A woman called the "godmother" of a mafia-style gang in China's southern city of Chongqing was sentenced to 18 years in prison Tuesday for running underground casinos and bribing government officials.

The trial of Xie Caiping is part of a months-long crackdown in the city that has exposed widespread government and police involvement in providing cover to numerous local gangs, or "black societies." It has also riveted China's state-controlled media with tales of a violent underworld.

Twenty-one others were sentenced to between one and 13 years in prison, according to a notice on the Chongqing court Web site.

The crackdown in Chongqing has been extensive, netting more than 1,544 suspects -- gangsters, prominent businessmen and 14 high-ranking officials. Six gang members in the city have already been sentenced to death for crimes including murder and blackmail, the first among hundreds expected to go on trial.

Xie, 46, is the sister-in-law of the city's long-serving deputy police chief, who was detained for investigation by the ruling Communist Party in August. He is regarded as being the center of an extensive network of protection of local gangs for over a decade.

She cursed in court when her trial started, which drew a rebuke from the judge but delighted the public, which has reveled in tales in the local media that she kept 16 lovers.

Chen Yanling, a Chongqing resident who says she was beaten by thugs after refusing a corrupt policeman's request to turn her teahouse into a casino, said she and other victims waited outside the court for the sentence. But they were angered by the result, with some people refusing to leave until police escorted them away.

"We didn't believe our ears when we first heard it's just 18 years. How many crimes has she committed?" Chen said.

The court notice said Xie's gang "severely broke the normal order of society," and illegally detained others and allowed loan sharking at the casinos.

The casino took a cut of the profits won by gamblers, the notice said. It said casino bosses hired stand-ins to take the blame when there was a crackdown and paid bribes to judicial officials.

No. 5 Intermediate People's Court said Xie earned more than 2 million yuan ($293,000) from the illegal activities.