Turkish prosecutors are reportedly investigating why the policeman who assassinated Russia's envoy to Turkey was not captured alive.
Russian ambassador Andrei Karlov was shot in the back as he gave a speech at an Ankara art gallery on Monday.
His killer was named by the Turkish interior minister as Mevlut Mert Altintas, a 22-year-old policeman, who shouted "Don't forget Aleppo, Syria" during the shooting.
Turkey's state-run Anadolu news agency said prosecutors were investigating why Turkish special forces, which stormed the gallery after the killing, did not take Altintas alive.
Initial findings suggest he continued to fire at police officers, shouting: "You cannot capture me alive!" Anadolu reported.
The officers shot Altintas in the legs, but he continued to return fire while crawling on the ground, the agency said.
President Recep Tayyip Erdogan has defended the police actions.
"There is some speculation about why he wasn't captured alive. Look what happened in Besiktas when they tried to capture an attacker alive," Mr Erdogan told reporters, referring to twin bombings this month outside the stadium of Istanbul's Besiktas football team.
Around 11 people have been detained in connection with the attack, including Altintas' parents, sister, three other relatives and his roommate.
Anadolu said investigators were also trying to determine whether anyone from the Russian Embassy may have providd the gunman with informaiton about Mr Karlov.
Mr Erdogan told reporters that Turkey's intelligence agency was also looking into Altintas' possible foreign connections, saying there were "certain clues" indicating overseas links. He did not elaborate.
Deputy Prime Minister Numan Kurtulmus, speaking to Turkish state television TRT, also said the gunman is not believed to have acted alone.
"This is not an ordinary attack that was conducted by a lone man," Mr Kurtulmus said. "There are some people who directed [him] behind the scenes, who led him into carry out such a plan, who wanted to obtain political gains."
"Those who are behind this pawn wanted to disrupt... Turkish-Russian relations in an irreparable way. But they won't succeed," he added.
Additional reporting by agencies
