Police are searching for a 170-175 centimeters tall man with a short haircut. He was wearing blue jeans and a brown sweater.
The Russian Investigative Committee plans to conduct additional investigating actions with Anna Duritskaya who was with Nemtsov when he was killed.
According to the Russian Interior Ministry, Nemtsov was killed in the center of Moscow at 11:40 p.m. local time on Friday (20:40 GMT), when several shots were fired at him from a passing car.
Putin said the murder was "vile and cynical" and claimed that it was likely a contract killing.
The Russian Investigative Committee is at the moment considering several crime scenarios, with some of them linking the politician's murder to events in Ukraine, the Charlie Hebdo terrorist attack in Paris and Nemtsov's business activity.