Russian investigators are continuing to probe last Sunday's crash landing of an Aeroflot passenger jet that killed 41 people.
Local media say investigators increasingly believe the fire started due to pilot error after the plane was struck by lightning.
Russia's Investigative Committee has opened a criminal case and is looking into whether the pilot violated air safety rules.
No official reason has been given,.... but authorities are considering equipment failure from a lightning strike as the primary cause of the crash.