South Korean navy officials filed an injunction yesterday against the release of a documentary questioning Seoul's claim that North Korea was behind the 2010 sinking of the warship Cheonan. The naval corvette sank with the loss of 46 lives on the night of March 26, 2010 near the South's disputed Yellow Sea border with the North. An investigation by a South Korean-led international commission concluded it had been sunk by a torpedo from a North Korean submarine - a charge Pyongyang has always denied. The documentary film Project Cheonan - to be released next month - was produced by the prominent left-wing filmmaker Chung Ji-young and highlights various theories that cast doubt on the commission's findings. It cites several experts who question the result of the investigation, including one who suggested the warship had probably sunk after colliding with a submarine of unknown origin. The film has angered the military. Three naval officials, together with two relatives of sailors who died on the Cheonan, signed the injunction request filed in a court near Seoul. "There is freedom of expression but no freedom of distortion," their lawyer Kim Yang-hong said. "The movie only focused on those who were raising suspicions without mentioning the result of the official investigation," he said, adding the film would spark "social chaos". A navy spokesman said the movie "seriously distorts facts and tarnishes the reputation of those who are related to the incident". There was further tension in 2010. In November, the North shelled a South Korean border island, killing four people including two civilians and sparking brief fears of a full-scale conflict.