The Mi-2 helicopter crash that killed one and left four injured might have been caused by a technical malfunction or a piloting error, a source in the emergencies services told TASS on Tuesday.

"The cause of the Mi-2 crash landing is being identified. There are two options - it was either a technical malfunction or a piloting error," he said, adding that the helicopter was seriously damaged.

A Mi-2 helicopter, which was on an medevac flight from the village of Sharya to Kostroma, crashed some four kilometers of Kostroma’s Sokerkino airport on Tuesday evening. There were five people: two pilots, two medics and a patient onboard. The patient died in the crash and the four others were hurt. They were evacuated from the site by helicopters.