The Istanbul Public Prosecutor’s Office has launched an investigation into the Acting US Attorney for the Southern District of New York (SDNY) Joon H. Kim, former SDNY Attorney Preet Bharara, and some others who are involved in the prosecution of the Turkish Iranian gold trader Reza Zarrab.

The investigation was launched on the grounds that the documents used in Zarrab’s case may have been stolen docs, fraud or of unknown content, a statement by the Istanbul Prosecutor’s Office read on Saturday. The investigation implicates Bharara, Kim and some other personnel of the prosecutor’s office.

Last year, Zarrab was charged by Bharara in Manhattan with conspiring to violate US sanctions on Iran, however he has recently failed to appear in court hearings before a final hearing, scheduled on Nov 27, raising allegations that he has agreed to cooperate.

Erdogan earlier demanded the release of Zarrab as well as the firing of former US Attorney Bharara, during a private meeting with then-US Vice President Joe Biden on Sept. 21, 2016, devoting half the 90-minute conversation to Zarrab, David Ignatius wrote for The Washington Post on Oct. 12.

Zarrab was the prime suspect in a major corruption investigation in Turkey that became public in December 2013 in which with others from the inner circle of the ruling Justice and Development Party (AKP) government and then-Prime Minister Recep Tayyip Erdoğan for having paid Cabinet-level officials and bank officers bribes to facilitate transactions benefiting Iran. After Erdoğan cast the case as a coup attempt to overthrow his government orchestrated by his political enemies, several prosecutors were removed from the case, police were reassigned and the investigation against Zarrab was dropped in Turkey.

Turkey’s former economy minister Zafer Caglayan, a former suspect in the Turkish bribery investigation, was also charged in the Zarrab case in US.