Twelve people, including the brother of a former mayor, were detained on Wednesday in an investigation into corruption in Istanbul’s Bayrampaşa district municipality. Mayor Hasan Mutlu from the main opposition Republican People’s Party (CHP) was arrested last September in the same probe. Another suspect remains at large.

Istanbul Chief Prosecutor’s Office said in a statement that the suspects were identified through accounts of plaintiffs, eyewitnesses and suspects captured in an earlier operation who collaborated with authorities.

The probe focuses on allegations of bribery of municipal officials and tender rigging involving the municipality that governs a district of about 275,000 people on the city’s European side. In September 2025, Mutlu and 20 others were arrested in the first wave of anti-corruption operations in Bayrampaşa. Mutlu was suspended from office and the ruling Justice and Development Party (AK Party), which long governed Bayrampaşa, won the mayoral election last October.

CHP-run municipalities across Türkiye are mired in corruption allegations. Most cases have been in Istanbul. The city’s mayor, Ekrem Imamoğlu, was arrested in March 2025 in a wide-ranging probe where he is accused of running a criminal network thriving on bribes and tender-rigging.

Prior to Imamoğlu’s arrest, authorities had ordered the arrest of Rıza Akpolat, mayor of Istanbul’s Beşiktaş district, on similar charges in late 2024. The investigation was expanded to include mayors of Adana province, the mayor of Istanbul’s Avcılar district, and mayors of Adana’s Seyhan and Ceyhan districts. At the heart of investigations were the confessions of Aziz Ihsan Aktaş, a businessperson who bribed mayors and municipal officials to secure public tenders. Akpolat and 193 other suspects will appear before an Istanbul court on Jan. 27.

Muhittin Böcek, the CHP mayor of Antalya, is another high-profile figure in corruption investigations. Böcek was arrested on July 5 and is expected to attend the first hearing in 2026, of a trial where he will face charges of rampant corruption, involving bribes. New hearings in trials of other CHP mayors, including former Izmir Mayor Tunç Soyer and the mayors of Istanbul’s Beykoz, Şile and Gaziosmanpaşa districts, also on charges of corruption, will be held throughout this year.