ANKARA - The gunman who killed the Russian ambassador to Turkey in an attack at an art gallery on Monday evening was a police officer who worked for the Ankara riot police, Turkey's interior minister said. Suleyman Soylu told reporters that the assassination 'has deeply' saddened the Turkish nation, saying it came at a time when Turkey and Russia had improved relations. Soylu also said that three other people were wounded in the attack, none seriously, and that one had been released already.