Authorities have accused a Chinese tycoon and his associates of running one of the country's biggest mafia gangs in recent years whose takedown has exposed ties between organized crime, police and officials.

The official Xinhua News Agency said Thursday the high-level prosecution centers on Liu Han, the former multimillionaire chairman of energy conglomerate Sichuan Hanlong Group, and his brother, Liu Wei.

Xinhua says the brothers have been charged with 15 crimes including murder, assault and illegal detention. The gang they allegedly ran amassed 40 billion yuan ($6.5 billion) in assets with businesses in energy, real estate and mining.

The bust appears to be part of a sprawling shakeup of Sichuan province that has ensnared senior politicians and influential businessmen, some of whom are believed linked to China's former security czar.