The girlfriend of Russian opposition leader Boris Nemtsov, who was with him when he was gunned down near the Kremlin last weekend, said Monday that she didn't see the killer.
Nemtsov was crossing a bridge with Anna Duritskaya, a 23-year-old Ukrainian model, when investigators say he was shot four times in the back from a passing car.
In her first public comments since the killing, Duritskaya said in an interview with Russia's independent Dozhd television she had dinner with Nemtsov and they were then crossing the Bolshoi Moskvoretsky Bridge in the direction of his apartment when he was killed shortly before midnight.
She said the assailant had approached them from behind and that a light-colored vehicle drove away from the scene of the shooting, but that she didn't see the assailant nor remember the make or license plate of the car.
Investigators said they are looking into several possible links for Nemtsov's slaying, including an attempt to destabilize the state, Islamic extremism, the Ukraine conflict and his personal life. They have offered a reward of nearly $50,000 for any information.
The Ukrainian foreign ministry tweeted late Monday that Duritskaya had left Russia and was returning to her family in Kyiv.
In an interview with Reuters news agency at the White House Monday afternoon, U.S. President Barack Obama said said Nemtsov's murder is a sign of a worsening climate in Russia where, he said, civil rights and media freedoms have been rolled back in the last several years.
"This is an indication of a climate at least inside of Russia in which civil society, independent journalists, people trying to communicate on the Internet, have felt increasingly threatened, constrained. And increasingly the only information that the Russian public is able to get is through state-controlled media outlets.''
Obama said he had called for a full investigation into the incident.
He said the killing is "part of what has allowed, I think, Russia to engage in the sort of aggression that it has against Ukraine.''