Investigators finished work at the scene of the helicopter in Altai
In Altai, investigators finished work at the site of the Gazpromavia helicopter, which killed 7 people, including the presidential representative in the State Duma, Alexander Koskopkin. The inspection lasted three days. The survey of all eyewitnesses is completed, the West Siberian Investigation Department said. The investigation works out four versions - adverse weather conditions, the human factor, the refusal of the helicopter mechanisms and poor -quality fuel.