Turkish media reports say a new suspect has been detained in connection with the December assassination of Russia's ambassador to Turkey.
Police detained the suspect in Ankara on February 15, the state-run Anadolu news agency cited an unidentified security source as saying.
Anadolu said authorities believe the suspect had telephone conversations with Mevlut Mert Altintas, the off-duty policeman who shot Ambassador Andrei Karlov dead at a photo exhibition in Ankara on December 19.
The 22-year-old Altintas shouted "Don't forget Aleppo" and other apparent references to Russia's involvement in the Syrian civil war, during the attack. He was later killed by police.
Anadolu said the suspect apprehended on February 15 is one of four -- including a police officer -- currently in custody in connection with the investigation.