A female Russian citizen allegedly connected to the suspected assassin of Russian Ambassador to Turkey Andrey Karlov has been detained in Ankara, Turkish media cited a law enforcement source in its report Monday.

Investigators suspect Ekaterina, 33, of maintaining telephone contacts and exchanging WhatsApp messages with off-duty police officer Mevlut Mert Altintas into late November, according to the Hurriyet daily.

The Russian Embassy in Ankara has so far been unable to comment on the arrest to reporters.

Altintas shot Karlov at the opening of an art gallery exhibition on December 19, an act Moscow regards as a terrorist attack, and was killed by police at the scene.