YEKATERINBURG, Russia, May 6 (UPI) -- Russian investigators said Monday the crash of a single-engine utility plane in June could have been due to technical malfunction, pilot error or poor weather.
Hunters on Sunday found the remains of 13 people and the wreckage of the Antonov An-2 biplane, which was reported missing from an airfield in the town of Serov on June 11, RIA Novosti reported.
Officials recovered the remains of 13 bodies, two of which are believed to be that of Serov's chief of traffic police and his subordinate inspector.
Regional police allege the plane was taken by pilot Khatib Kashapov and a group of friends while they were drinking.
The plane crashed in a remote, mountainous area in the Urals about five miles from where the plane took off.
Officials called off the search for the crash site in November due to bad weather and had planned to resume this spring, RIA Novosti reported.
Russia's Investigative Committee said Sunday it has re-launched a criminal probe into the hijacking and crash.
The committee alleged there was a breach of flight safety rules and the rules of aircraft operation that caused the deaths of more than two people from carelessness, RIA Novosti reported.