The Warsaw district prosecutor's office says a key witness in the investigation of 2010's Polish presidential plane crash is dead.
The prosecutor's office said that Remigiusz Mus was found hanged in his home near Warsaw on October 27.
He was a flight engineer on a Polish airliner that landed in Smolensk, Russia, on April 10, 2010, just an hour before the crash that killed President Lech Kaczynski, his wife, and Poland's top public and military figures.
Mus testified during the investigations that a Russian air-traffic controller had allowed the presidential plane to descend to the "landing decision point height" of 50 meters, despite dense fog.
This contradicted the official Russian version of events that said the controller did not allow the airliner to descend lower than 100 meters.
With reporting by ITAR-TASS