The Russian pilot who sent a Boeing 737 into a near-vertical dive, killing all 50 people on board, might have had a fake license, Russian investigators said Friday.

Investigative Committee spokesman Vladimir Markin said his team believes that some pilots working for small regional airlines in Russia have not been properly trained but managed to get fake licenses in centers certified by the country's aviation agency.

Markin said the pilot who sent the Boeing 737 into a dive after an aborted first landing attempt in the city of Kazan had received his license from a small training center that has since been shut down.