The gunman who assassinated the Russian ambassador in Ankara was a 22-year-old off-duty Turkish cop who had been investigated for an attempted coup in July, according to reports.

Mevlüt Mert Altıntaş, a member of the Turkish capital’s riot police, was not on duty when he stood behind Ambassador Andrey Karlov as he gave a speech at an art gallery, the Russian Sputnik news agency reported.

Altıntaş, who managed to enter the gallery using a police ID, was wearing a suit and tie – a “police bodyguard uniform” — before drawing his pistol and shooting Karlov at least five times in the back.

He shouted “Allahu Akbar!” – Arabic for “God is great!” – and, “You Russians destroyed Aleppo and Syria!” the Mirror of the UK reported.

But Ankara Mayor Mayor Ibrahim Melih Gökçek believes Altıntaş’ motives had more to do with his following of Turkish preacher and former imam Fethullah Gülen and not Syria, Reuters reported.

Gülen fled Turkey in 1999 and has lived in self-imposed exile in the Poconos.

Gökçek said Altıntaş may have been a member of the Haberturk terror group and had tied to Gülen’s Islamist transnational religious and social movement.

Turkish President Recep Tayyip Erdoğan has blamed Gülen for orchestrating the July coup attempt and has demanded that the US extradite him to Turkey.

“This man is the leader of a terrorist organization that has bombed my parliament,” Erdoğan said in an interview on “60 Minutes,” the International Business Times reported.

“We have extradited terrorists to the United States in the past, and we expect the same thing to be done by the United States,” he said.

Gülen has denied involvement in the uprising, which killed more than 250 people.