Park Geun-hye was the first leader of South Korea to be forced from office in response to popular pressure since the founding president, Syngman Rhee, fled into exile in Hawaii in 1960 after protests against his corrupt, authoritarian rule.
South Korea's ousted President Park Geun-hye has been formally indicted on corruption charges.
Jay Y. Lee, the chief executive of the Samsung Group, is under arrest facing allegations of briging Park and her friend, Choi Soon-sil. Its acting head Lee Jae-yong and Ms Choi are in the same detention centre as Ms Park awaiting trial. Park was also prosecuted on charges of abuse of power for ordering the administration to create and enforce a blacklist of artists critical of her.
Ms Park has denied all the charges during her five rounds of questioning in jail, saying she only got help from Ms Choi to edit some presidential speeches and public relations advice. Impeached by lawmakers late past year and officially removed from office by the country's high court last month, the former leader now faces the prospect of life in prison.
Now Choi faces an additional charge of bribery involving Shin, the prosecutors said.
Park is accused of leaking state secrets to Choi, a high school graduate with no title or security clearance, and letting her handle a wide range of state affairs including senior nomination. It is still unclear if the trial will start before a May 9 special election that will determine her successor.
Park was arrested by South Korean authorities on March 30. Lee and Choi are both on trial and deny wrongdoing.
Park's downfall and the presidential election in South Korea also have the potential to rattle the delicate balance of worldwide diplomacy in Asia at a time of heightened tensions with North Korea.
Park is suspected of colluding with Choi to extort donations worth 77.4 billion won ($69.6 million) from local firms, including Samsung Group, for the Mir and K-Sports foundations controlled by Choi in return for political favors. The eldest daughter of strongman dictator Park Chung-hee, Ms Park's election in December 2012 brought her back to the Blue House where she spent her formative years and served as acting first lady after her mother Yook Young-soo was assassinated in 1974.