The prosecution sought an arrest warrant for former presidential aide An Chong-bum on Friday, accelerating its probe to question more of President Park Geun-hye’s close associates involved in the spiraling scandal.

Prosecutors charged An, the ex-presidential secretary of policy coordination who is currently under emergency detention, with abuse of power, accusing him of forcing local firms including Lotte Group, SK Group and Posco to contribute money to the Mir and K-Sports foundations.

An was also charged with attempted coercion for his role in threatening a midsize ad company, which bought Posco’s in-house advertisement company Poreka, to hand over its shares to a third party associated with Cha Eun-taek, a close confidant of Choi Soon-sil, President Park’s feud-ridden friend.

An maintains that he has never met Choi and companies voluntarily contributed money to the foundations.

The court will hold a hearing to review the warrant application Saturday.

The move came a day after Choi, who holds no public post, was formally arrested late Thursday night for being an accessory to An’s abuse of power and attempting to commit fraud.

Top prosecutor Kim Soo-nam ordered the expansion of the current investigative team to thoroughly investigate the allegations surrounding President Park’s civilian friend Choi, who is accused of meddling in state affairs and coercing businesses for funds. Ten prosecutors will be added to the current 22, making it the biggest-ever team under the prosecution.

Prosecutors arrested Jeong Ho-seong, a former secretary in charge of the president’s private affairs, late Thursday night for allegedly leaking confidential presidential speeches and documents related to diplomacy, security and economy to Choi.

Jeong was one of Park’s closest aides, along with Lee Jae-man and Ahn Beong-guen.

Next in line to face the probe is likely to be Woo Byung-woo, a former presidential secretary of civil affairs. The prosecutors are likely to call him in soon for questioning over allegations that he siphoned off his family-owned company’s funds, falsely reported his assets and used his influence to get his son assigned to a relatively easy post while serving mandatory military service.

The prosecution is seen widening its probe after finding itself in the hot seat over what critics see as lukewarm efforts to investigate influence-peddling allegations and the lenient charges it brought against Choi, a central figure in the burgeoning scandal engulfing the Park administration.

President Park said Friday that she would cooperate with prosecutors for the probe. She could face questioning for allegedly leaking classified information to Choi and allowing her to interfere with state affairs.

The scandal erupted last week when a local TV channel reported to have found over 200 presidential documents on a trashed tablet PC purportedly used by Choi. The documents were said to include presidential speech scripts, with apparent signs of editing by the owner of the computer, and other documents that contained top-secret information on inter-Korean relations.

Investigators said Friday that they found traces of Jeong’s involvement on a tablet PC containing presidential documents. Lee Seong-han, ex-secretary general of the Mir Foundation, claimed in an interview with local media that Jeong delivered a 30-centimeter-thick report about the president and state affairs to Choi daily.

The prosecution allegedly concluded that the tablet PC belongs to Choi, despite her denial.

The prosecution is also considering summoning Ahn Bong-geun, who is suspected of helping Choi enter and leave the presidential office, and Cha Eun-taek, Choi’s close aide who allegedly exerted influence over state-led projects in the culture sector upon his return from China.

The prosecution is reportedly also investigating allegations involving Jang Si-ho, the daughter of Choi Soon-sil’s sister Soon-deuk, who is being accused of meddling in state affairs. It imposed a ban on her from leaving the country.

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)