Russian investigators were Monday seeking to determine the cause of a plane crash last June that killed all 13 on board, after the victims' remains were finally discovered following almost a year of fruitless searching.
Two hunters at the weekend stumbled upon the the An-2 plane in a marsh eight kilometres (five miles) outside the town of Serov in the Sverdlovsk region in the Ural Mountains in central Russia.
Investigators confirmed the wreckage belonged to the An-2 plane that disappeared in June 2012 after taking off on an unsanctioned flight, leaving Russian media to dub it the "ghost plane".
Months of intensive searches for the plane in the forests of Sverdlovsk and neighbouring regions yielded no results, and in the end the hunters accidentally came across the aircraft just outside Serov, the town from which it had taken off.
Thirteen corpses have been found inside the wreckage and DNA testing was now under way to formally identify them, Urals prosecutors said in a statement.
Russian media quoted local police as saying that the corpses were those of the pilot and 12 passengers, some of whom were high-ranking traffic police officials in the Serov region.
Investigators said three possible causes were being examined including "the technical condition of the plane, a mistake by the pilot and the weather conditions."
The failure of the search effort to recover the plane had fascinated Russian media, prompting numerous and sometimes fanciful theories about its fate.
The search, which focused on an area the size of western Europe, was so elaborate that it uncovered the wreckage of a small plane that disappeared in the 1980s and had been missing ever since.
But it was not clear why despite the major search effort, it was passers-by who spotted the wreckage not far from the town where the plane had taken off.
Regional police spokesman Valery Gorelykh told Russian news agencies that the passengers had been drinking before the flight and it was possible that the unsanctioned flight was merely for sight-seeing.
State news channel Rossiya-24 said that the the crash may have been caused by a sudden fall in the plane's altitude after the pilot lost consciousness.