Shooter in Russian Ambassador Killing Was Member of Turkish Riot Police, Used ID Card to Enter Building

— -- The man accused of assassinating Russia's ambassador to Turkey was a member of the riot police in Ankara, Turkey, who used his police ID card to enter the building before the shooting, according to Interior Ministry sources.

The suspect, identified as Mevlut Mert Altintas, was killed by the Turkish anti-terror police, the Interior Ministry said, after he allegedly shot the ambassador in an attack caught on camera.

According to Russia's state news agency, Tass, witnesses said the ambassador, Andrey Karlov, was shot in the back after he gave a speech at the Museum of Modern Art in Ankara, Turkey's capital city.

The alleged gunman, born in 1994, yelled in Arabic, "Allahu akhbar" (God is great).

He also yelled in Turkish, "Don't forget Aleppo. Don't forget Syria. Don't forget Aleppo. Don't forget Syria. Until these places are safe, you will not taste any safety either."

After the incident, Altintas' mother and sister were taken into custody in the Turkish city of Izmir.

The ambassador was dead by the time he arrived at the hospital, the Interior Ministry said.

Three other people were injured during the incident by ricocheting bullets but are said to be recovering.

Karlov, 62, was a career diplomat, according to The Associated Press. He joined the diplomatic service in 1976.

He served as Russia's ambassador to North Korea from 2001 to 2006 and later worked as the chief of the Foreign Ministry's consular department. He served as the ambassador to Turkey since 2013.

ABC News' Engin Bas contributed to this report.