A Russian woman allegedly linked to Mevlüt Mert Altıntaş, the assassin of deceased Russian Ambassador Andrei Karlov, was arrested by police in Ankara following her detention last month.

The woman, identified as Ekaterina B. had contact over the phone with Altıntaş, an off-duty police officer with suspected ties to the Gülenist Terror Group (FETÖ).

Their phone calls date back to November 2016, one month before Karlov, a career diplomat, was shot dead by Altıntaş in an art gallery in Ankara. The Russian diplomat was delivering a speech at the inauguration of an exhibition.

The 33-year-old Ekaterina B. was also accused of running a prostitution ring, catering to wealthy businessmen in Ankara.

The suspect, however, denied talking on the phone with Altıntaş, but admitted messaging via WhatsApp and running two websites offering sex services.

Police are still analyzing "digital evidence" and work to determine the nature of the ties between Altıntaş and Ekaterina B., who also has ties to the local Russian Culture Center.

Three other suspects, including two police officers, have already been remanded in custody.

Altıntaş himself was a riot policeman and was linked to FETÖ, which has been blamed for plotting the July 15 coup attempt last year.

The terrorist group is known for its widespread infiltration of law enforcement agencies and other police officers remanded in custody are also believed to be affiliated to the group.

Timur Özkan, organizer of the exhibition, was also taken into custody for his suspected links to fugitive FETÖ members, including alleged correspondence with a prominent journalist linked to the Gülenists.

Karlov was speaking at the opening of an exhibition on Russia, in an art gallery. Meanwhile, Altıntaş, though off-duty, sneaked in by showing his police ID and opened fire.

The Russian diplomat was killed on the spot while Altıntaş fled took refuge on another floor of the gallery and was later killed in a shootout.

The incident rocked Turkey as it was trying to restore ties with Russia following a crisis over the downing of a Russian jet for violating Turkish airspace.

Moscow and Ankara later assured that the incident would not harm relations.