President Park Geun-hye is suspected of complicity in her former senior secretary Cho Won-dong's unsuccessful attempt to force CJ Group's vice chairman to quit in 2013, prosecutors said Sunday, announcing their indictment of Cho on charges of attempted coercion.

A special investigation team of the Seoul Central District Prosecutors' Office indicted Cho, a former senior presidential secretary for economic affairs, without detention for coercing CJ Group Chairman Sohn Kyung-shik to dismiss his niece Lee Mie-kyung from the group's vice chairmanship in July 2013.

Prosecutors have already named Park a suspect in the abuse of power scandal involving her longtime friend Choi Soon-sil and her associates, saying the president colluded in Choi's efforts to force donations from large companies worth tens of millions of dollars. The National Assembly voted to impeach the president on Friday, suspending her from office pending a Constitutional Court decision.

Winding up their months-long investigation, prosecutors said Cho conspired with President Park in compelling Sohn on the phone in July 2013. Cho allegedly told the conglomerate chief that the group will be prone to serious backlashes if the CJ vice chairman does not come down from her post. 

Since CJ ultimately refused Cho's request, prosecutors indicted Cho for attempted coercion.

Prosecutors also announced the indictment of Kim Chong, a former vice culture minister, on charges of colluding with Choi and her niece Chang Si-ho to force conglomerates to donate billions of won to a winter sports foundation established by Chang.

President Park and her former senior secretary Ahn Jong-beom were separately accused of colluding with Choi and her associates in forcing an affiliate of the Korea Tourism Organization to create a wheelchair fencing team and give special favors to Choi's company through an agency contract.

The probe began in October when a civic group accused Park's confidante Choi and her associates of meddling in government affairs without holding any title in the administration and amassing wealth illegally by using their ties with those in power. 

Choi is currently awaiting trial for fraud and embezzlement.

With the launch of an independent counsel team this week, the prosecutors raised the need for further investigations by special prosecutors into suspicions of Park's third-party bribery in forcing or attempting to force top conglomerates, such as Samsung and Lotte, to extend financial support worth tens of billions of won to the Choi family.

Prosecutors also asked the independent counsel team to open investigations into former presidential chief of staff Kim Ki-choon and former presidential secretary Woo Byung-woo on suspicion of protecting Choi and her associates.

Prosecutors made public details of Choi's alleged involvement in state affairs.

Choi visited the presidential office Cheong Wa Dae at least 10 times illegally without going through the due identification process, prosecutors said, adding she mainly used a presidential secretary's vehicle to enter Cheong Wa Dae.

Prosecutors said they will hand over Ahn's notebooks that contained Park's instructions from January 2015 and October this year, and transcripts of phone conversations between former secretary for private presidential affairs Jeong Ho-seong and the president, as well as those between Jeong and Choi, to the independent counsel team.

In most conversations, Jeong listened to Choi's opinions about key state affairs after sending classified Cheong Wa Dae documents via Gmail from November 2012 to December 2014. They also held a total of 895 phone conversations and 1,197 text message exchanges from February 2013, when Park took office as president, to December 2014, prosecutors said.

Prosecutors said they confirmed a tablet PC, key evidence in the snowballing scandal that contained hundreds of classified Cheong Wa Dae documents, belongs to Choi, noting, for instance, that some messages in the PC were sent to Germany in July 2012 and July-August 2013, when Choi was staying in the European country for a visit.

Choi has been flatly denying ownership of the tablet, saying she does not even know how to use such a gadget.

Prosecutors have countered, based on digital forensic analysis and Choi's immigration records, that much of the location information kept on the tablet PC coincides with where she has been. They have also cited testimony from many people around her who said they saw her using it. (Yonhap)