Turkey has arrested two men suspected of spying for the United Arab Emirates and is exploring the possibility that they are linked to the assassination of Washington Post journalist Jamal Khashoggi, Anadolu state news agency said on Friday.

The two were detained as part of an investigation by Istanbul prosecutors into alleged spying by the Gulf state, Anadolu reported. It was not clear when they were arrested.

A critic of the Saudi regime, Khashoggi was murdered in the Saudi consulate in Istanbul on October 2 by a team of 15 agents sent from Riyadh. The Saudi national’s body has never been recovered.

After first denying the murder, Saudi Arabia later said rogue agents had carried out the operation.

A trial of 11 suspects opened earlier this year in Saudi Arabia.

Much of the case remains unclear, including the role of Saudi Arabia’s powerful crown prince and de facto ruler, Mohammed bin Salman.

Turkey has delicate relations with Saudi Arabia and the United Arab Emirates, two of the Arab states that imposed a blockade on Qatar, one of Ankara’s close allies.

Turkish President Recep Tayyip Erdogan has repeatedly said he would keep investigating Khashoggi’s murder and has criticized the lack of cooperation from Riyadh.

– with reporting by AFP