French police have detained a suspect that Dutch authorities say was the gunman in the killing of Turkish whistleblower Cemil Önal, a former finance manager for a slain casino operator who had accused high-level government figures in Turkey and northern Cyprus of taking bribes.
The Dutch Public Prosecution Service said on Monday that police in France detained a 34-year-old Turkish man with no known fixed residence on suspicion of fatally shooting Önal on May 1, 2025, on a hotel terrace in Rijswijk, a town near The Hague. Prosecutors said they suspect the man was the shooter and are seeking his surrender to the Netherlands under a European arrest warrant.
Dutch prosecutors said the suspect is currently being held in France in a separate weapons case and could be transferred to the Netherlands later this year.
Önal, 41, was shot dead in broad daylight in what Dutch police described as a targeted attack.
He was a Turkish national who had worked for years as the financial manager for Halil Falyalı, a casino owner and alleged crime boss in the northern part of Cyprus, which is under Turkish control, and later gave detailed accounts of suspected money laundering and covert payments involving Turkish and Turkish Cypriot political figures.
In interviews with Dutch investigative outlet Follow the Money and the Organized Crime and Corruption Reporting Project, Önal said Falyalı’s gambling operations generated tens of millions of dollars a month and that part of this money was moved through offshore companies in Curaçao and paid out as “sponsorships” to officials linked to ruling parties in Turkey and northern Cyprus.
Önal alleged that former Turkish vice president Fuat Oktay received $50 million in bribes and that Turkish Cypriot leader Ersin Tatar helped mediate the payment, while also alleging monthly payoffs to officials in Turkey and northern Cyprus.
Monday’s announcement is the latest step in a case that had already led to one earlier arrest. Dutch prosecutors said a 47-year-old man from Bergheim, Germany, was arrested in November 2025 in connection with Önal’s death and extradited to the Netherlands at the end of January. Prosecutors said the investigation into his possible role is continuing and that a court is due to decide in early April whether to extend his pretrial detention.
Dutch authorities have not publicly named the Germany-based suspect. However, Dutch media previously identified him as Bayram B., described as a former Turkish prosecutor who was allegedly sitting at Önal’s table when the shooting took place.
Prosecutors said the inquiry into another man who may have been involved in the murder is still underway.