The boat's captain, Dmitry Lavrentyev, was charged with abuse of authority and engineer Dmitry Grobov was accused of causing death by negligence. A jury acquitted both men on September 14, 2011, but the Supreme Court's military board overturned the verdict in May 2012 and ordered a retrial, which is now underway.

Russian media reports on the retrial on Monday claimed a video existed that was taken inside the Nerpa during the accident and that disproved several of the investigation's conclusions.

But Primorye Region investigators denied the existence of video filmed when the automated fire-extinguishing system was activated on the Nerpa.

A video related to the accident does exist, but it was made during hearings by experts to explain the operation of the submarine's automated control systems, a Primorye Region law enforcement source said on Tuesday.

"The [video] recording was made at the moment when an audio recording from the automated control systems was being decoded. The audio recording was included in the criminal case materials, but there was no point in including the video recording as it essentially duplicated the audio version," the source said.

The denial of the video's existence came the day after Acting Pacific Fleet Chief of Staff Rear Admiral Andrei Voitovich claimed a video existed that exonerated the crew, as it clearly showed the crew's reactions to the emergency situation on the boat.

“How could they ignore it, when the video – not the disk that the prosecutor’s office seized during the General Staff Commission's work – made it impossible to attribute the accident to the poor training of the crew?” Voitovich said.

Investigators have refused to add the video to the case materials, Voitovich told RAPSI on Tuesday, adding its whereabouts are unknown.

The prosecutor's office confiscated a disk immediately after the accident, Voitovich said, but it was impossible to play it outside the submarine except for on the premises of the Avrora ship control systems producer in Primorye, which has similar equipment. Avrora is a party to the dispute, as it developed the submarine's new Molibden computerized automated control system, Novaya Gazeta reported in May 2012.

This is not the first case in which prosecutors have provided biased information to the media, Voitovich claimed, adding they were trying to avoid the public criticism sparked by the retrial.