Bloggers have accused Russian authorities of lying in their claim that the murder of Boris Nemtsov just yards from the Kremlin was not captured on security footage, citing photographic evidence that shows a camera pointing directly at the scene of the crime.

The former deputy prime minister and outspoken critic of Vladimir Putin was killed by four bullets to the back as he strolled across Bolshoi Moskvoretsky Bridge with his Ukrainian girlfriend Anna Duritskaya on Friday evening. Duritskaya spoke to the press for the first time on Monday and told the liberal online channel Dozhd that the killer had come from behind them, but added that her memory of the night is hazy.

The federal protection service, which is in charge of guarding the Kremlin and high-ranking officials including Putin, told state news agency RIA Novosti on Monday that although its security cameras were functioning on Friday evening, they did not capture the shooting of Nemtsov. Bolshoi Moskvoretsky Bridge is not within its "zone of responsibility" and its "security cameras are directed at the Kremlin and provide a view of the inner territory," a representative said.

Previously, publications including the newspaper Kommersant had reported that "recordings from security cameras in the area were either not discernible or were completely absent because they were turned off for renovation work."

But following the protection service's statement, well-known photographer, blogger and activist Mitya Aleshkovsky posted a photograph of security cameras on the nearest Kremlin tower which he said he took shortly after Nemtsov's death. One camera was clearly pointing outward, in the general direction of the bridge.

"Of course the federal protection service is lying when it says that not one security camera filmed the moment of the murder because they were directed at the Kremlin," Aleshkovsky wrote on his Facebook account. "I deliberately took this photo from the bridge on the night of Nemtsov's murder. And I asked other photographers to do the same … The camera on the Beklemishevskaya tower was pointed DIRECTLY at the place of the murder."

A video of the bridge taken from afar by a television station's traffic camera allegedly filmed the murder, but the actual shooting was obstructed by a slow-moving municipal truck. After the truck passes the walking couple, a man is seen quickly getting into a passing car and leaving the scene.

Duritskaya told Dozhd on Monday that she had not seen the killer, who was behind them. After the shooting, she turned around and saw a light-colored car, she said. Many have suggested the assassin was lying in wait for Nemtsov in the stairway leading up from the bank of the Moskva River.

Russia's investigative committee is questioning Duritskaya and has said Nemtsov could have been killed in connection with "internal Ukrainian events," hinting he was killed by the Kiev government that he so vocally supported. It has also said the assassins could have been Islamic terrorists angry over Nemtsov's solidarity with the Charlie Hebdo cartoonists.