Poland's government on February 4 opened a new investigation into the 2010 plane crash in Russia that killed President Lech Kaczynski and dozens of other state leaders.
The new probe comes amid already deeply strained relations between Warsaw and Moscow.
Announcing the investigation, Defense Minister Antoni Macierewicz said the original probe had been riddled with "mistakes" and "abnormalities."
He said there will be 21 members of the new investigative commission, including engineers and other technical experts. There also will be four advisers from abroad.
The original investigations by Poland and Russia determined that the crash near Smolensk, Russia was an accident that resulted from pilot error and bad weather.
But Jaroslaw Kaczynski, the late president’s twin brother who heads the governing Law and Justice party, has suggested the crash was an assassination and has implicated Russian President Vladimir Putin.
Among those killed was a huge swath of Poland’s political and military elite -- the first lady, the head of the central bank, military leaders, and other leading figures.