From what I've read about the accident it seems that there are signs that the plane was sabotaged and started losing parts in air, long before it hit the trees. The Polish version is different from the Russian one, where it was said that the plane was flying too low, hit the trees and crashed. I like conspiracy theories, so I'm willing to believe in the sabotage, especially that the Russians refused to send the wreckage to Poland for examination.
As you said, the Polish version of this incident is totally different from the Russian one.
It is pretty funny, because I heard that many Poles are considering this as a assasination, because they simply dont believe that the plane with so many important authorities would crash, on the land of Russia.
And the Putin refused sending back the crashed plane to Poland, what is the cause of even more feed going to this conspiracy theory, which seems for me as something funny, because that makes no logical sense from the perspective of Russia.
What goal would Putin achieve with that, because it could only turn on Poles against the goverment of different country, however I need to admit that it is actually suspicious, that they didn't send the wreckage.
They believe in the assassination because there were actual assassinations that followed the crash. Former Polish minister, who threatened to reveal classified documents was found hanged in his office a couple weeks later. At first glance a suicide, but all shoe prints, including his own, were wiped from the floor and the window behind him was open.
There was also a case of the former commander of Polish special forces, who openly said that it was a military plane and the incident should be handled by NATO, just like any military crashes on foreign soil. He was shot in the head with his own weapon, the police said it had to be suicide, because there were no other fingerprints on the weapon.
![Cheesy](https://bitcointalk.org/Smileys/default/cheesy.gif)
Both of them didn't say anything to their families and didn't leave any notes. Both acted normal before death.