The head of Turkey’s capital markets regulator resigned on Monday, citing health concerns, as the country grapples with the fallout from a sprawling investment fund scandal, media reports said.

Mahmut Sütcü, who became chairman of the Capital Markets Board (SPK) in May, stepped down just days after prosecutors received official approval to investigate his predecessor in connection with the scandal.

Deputy Treasury and Finance Minister Osman Çelik also submitted a retirement request Monday, the state-run Anadolu news agency reported, citing ministry sources.

Çelik’s son-in-law, İskender Balcı, a former board member of shipbuilder Özata Denizcilik, was jailed pending trial earlier this month in a stock manipulation case linked to the fund scandal.

Balcı’s father, Mustafa Balcı, is a former board member of Turkey’s Banking Regulation and Supervision Agency (BDDK).

The crisis hit the headlines just over a month ago, prompting prosecutors to open an investigation into allegations of widespread market manipulation.

It began when several funds were unable to meet investors’ withdrawal requests. Regulators placed seven firms managing 131 investment funds into liquidation, with the funds’ assets reportedly worth about $17 billion.

Regulators say some 455,000 individual investors are affected.

The scandal has put pressure on President Recep Tayyip Erdoğan’s ruling Justice and Development Party (AKP), with one senior party official resigning after allegations about her investment activities.

On Wednesday, Finance Minister Mehmet Şimşek authorized prosecutors to investigate former SPK chairman İbrahim Ömer Gönül, whose four-year term ended in April.

In a letter to the ministry, prosecutors said there were “clear and sufficient indications” that Gönül had failed to fulfill his responsibilities during his tenure.

So far, 85 people have been arrested in connection with the affair, according to the Justice Ministry.

Separately, police have detained five journalists in connection with the scandal, accusing them of spreading misinformation.

Mustafa Balcı of the pro-opposition Sözcü daily and Şaban Sevinç of the online news channel Bizim TV were jailed pending trial on October 9 over an image on X suggesting a link between AKP spokesman Ömer Çelik and a key suspect in the fund investigation.

Two others, Sözcü TV presenter İsmail Saymaz and Murat Ağırel, an investigative journalist and columnist for the Cumhuriyet daily, were placed under house arrest over a report questioning investments by the trade minister.

On Thursday, Bahadır Özgür, a journalist for Halk TV’s website who has written extensively about the scandal, was detained. He was conditionally released the following day.

Also on Friday, police again detained Ağırel in a separate investigation into alleged money laundering.

Agence France-Presse, with reporting from Turkish Minute