Ambassador's Death Complicates Russian, Turkish Cooperation in Syria

— -- The brutal assassination of the Russian ambassador to Turkey during a televised event at the Museum of Modern Art in Ankara on Monday left observers shocked and appalled, but also asking difficult questions about the relationship between Turkey and Russia.

The shooter has been identified by local police as Mevlut Mert Aydintas, 22, a member of Ankara’s riot police. Aydintas stood over the slain ambassador's body, shouting in Turkish to terrified onlookers: "Don't forget Aleppo, don't Forget Syria," and "God is greatest."Shortly after he was gunned down by security forces.It is not yet clear if Aydintas was connected to any known terror groups or if he was motivated or working as part of a wider plot. Local police say they are still investigating many leads and have taken into custody at least seven people for questioning, including members of Aydintas’ family and his roommate.Nevertheless, the shooter's own words explain at least some part of his apparent motivation: the war in Syria.

Syrian War

The United States

Erdogan blamed the failed coup on the movement of Fethullah Gulen, a exiled cleric living in Pennsylvania. The Gulen movement is designated as a terrorist organization by the Turkish government, which has equated the group’s leader to Osama bin Laden. Turkish leaders said Washington's failure to immediately extradite Gulen had "negative" effects on their relationship.Turkish officials have even accused the assassin in Ankara as being a member of the Gulenist movement.

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ABC News' Patrick Reevell and Marcus Wilford contributed to this report.