Lech Kaczyński, the President of Poland, died in the crash of a Polish Air Force Tu-154, at Smolensk-North airport in Russia, on 10 April 2010.
Polish investigators have found traces of explosives on the wreckage of the president's jet, daily Rzeczpospolita reported on 30 October 2012.
The newspaper said prosecutors and explosive experts who examined the remains of the plane found signs of TNT and nitroglycerin on the wings and in the cabin, including on 30 seats.
Traces of explosives were also found in the area where the Tu-154 crashed, the daily reported.
Poland found explosives on wreckage of president's plane-report
On 29 October 2012, we learn that:
A flight engineer, Remigiusz Muś, who was due to deliver key evidence, has been found hanged in his house in Warsaw.
Muś had arrived in Smolensk on an airliner carrying the Polish press pool one hour before the President’s plane crashed. Shortly after the incident, Muś retired from aviation.
'Key witness' in Polish presidential plane crash dies
In January 2012, a Polish prosecutor involved in the investigation shot himself for no apparent reason during a media briefing.
Doctors managed to save his life.
Who wanted Poland to change its policies?
Jaroslaw Kaczynski, twin brother of Lech, is the former Prime Minister of Poland.
In his book, 'The Poland of Our Dreams,' Jaroslaw Kaczynski suggests that Germany would like to grab the areas in western Poland that Germany stole in 1939, after Hitler did a deal with Stalin.
"Angela Merkel belongs to a generation of German politicians that would like to reinstate Germany's imperial power," writes Kaczynski.
"A strategic axis with Moscow is part of that."
He also states his opposition to German investment in western Poland. "We could wake up to a smaller Poland one day," he warns.
Kaczynski also writes in the book that the former East German secret police, the Stasi, could have helped Merkel, who grew up in East Germany, to gain power.
"I don’t think that the awarding of the chancellorship to Angela Merkel was pure chance," he writes
"Poland was the only member of the 27-nation European Union to have experienced growth in 2009 and the IMF forecast that its economy would expand by 2.75 percent this year and by 3.25 percent in 2011...
"Kaczynski frustrated some of his opponents by being in no rush to head towards the euro party,” the Daily Telegraph reported."