A court in Istanbul is expected to deliver a verdict in a massive trial where a businessman is accused of collaborating with several opposition mayors in rampant tender corruption.

Aziz Ihsan Aktaş is at the heart of the trial. He was previously released under judicial control after collaborating with authorities and detailing how he paid off mayors and municipal bureaucrats to secure business with municipalities in Istanbul and elsewhere. The first hearing in the trial was held on Jan. 27, one year after Aktaş and several mayors from the Republican People’s Party (CHP) were arrested on corruption charges.

A total of 200 defendants, including seven mayors, are on trial in the case. The next hearing will be held in a massive courtroom-prison complex in Istanbul’s Silivri district on Monday.

The initial operation of the investigation launched by the Istanbul Chief Public Prosecutor's Office was conducted on Jan. 13, 2025. As the process continued, numerous suspects were detained; while some were formally arrested, judicial control measures were applied to others.

In the prosecution's 579-page indictment, completed on Oct. 20, 2025, Beşiktaş Municipality, Avcılar Municipality, Esenyurt Municipality, and two subsidiaries of the Istanbul Metropolitan Municipality (IBB) were named as "injured parties," and 19 individuals were listed as "victims." The indictment seeks multiple prison terms for Aktaş on charges of establishing a criminal organization, rigging public tenders, forging official documents, committing fraud to the detriment of public institutions, offering bribes, laundering crime-derived assets, and issuing fraudulent invoices.

Among the indicted officials are the mayors of Istanbul’s Avcılar, Esenyurt, and Beşiktaş districts, as well as the mayors of two districts in the southern province of Adana, Adana's metropolitan mayor, and the mayor of the eastern province of Adıyaman.

Aktaş has also testified in a separate corruption case involving former Istanbul mayor Ekrem Imamoğlu. During a hearing last Monday, Aktaş described to the court an alleged system of pressure and extortion within the Istanbul Metropolitan Municipality (IBB). He claimed this scheme was designed in part to finance Imamoğlu’s political career as the sprawling trial involving 414 defendants continued.

Aktaş, who is being tried without pre-trial detention, presented his defense at the 68th hearing of the case before Istanbul’s 33rd High Criminal Court. Fifty-three of the 414 defendants are currently in custody.

The case centers on prosecutors’ allegations of a criminal organization led by Imamoğlu. The defendants face various charges of corruption involving the municipality and its affiliates.

Aktaş alleged that outstanding payments owed by municipal bodies were deliberately withheld to pressure businesses into making illicit payments. He claimed that companies refusing to comply faced threats of financial penalties, contract terminations, or obstruction with zoning and licensing procedures.

“One of the primary purposes of the system was to finance Ekrem Imamoğlu’s political career,” Aktaş told the court. He described a recurring pattern in which payments legitimately owed to contractors were delayed until business owners agreed to provide the money demanded by individuals tied to the network.

He testified that these payments were not deposited into municipal or official donation accounts, but were instead withdrawn in cash and delivered to intermediaries at locations including hotels and private offices. “The people, dates, and companies were different, but the method was always the same,” he said. Aktaş argued that the operation could not be explained as the isolated actions of lower-ranking municipal officials.

He further claimed that, in one instance, a demand for money was explicitly conveyed to him as an “instruction from Ekrem Imamoğlu,” while in another, he was warned that payments owed to his companies would be withheld if he did not comply.