UK lab to help Polish inquiry into president's plane crash death
Polish prosecutors investigating the 2010 plane crash which killed President Lech Kaczynski and 95 others have sent samples from the plane for laboratory tests in the UK to find out if an explosion caused the disaster.
Ewa Bialik, spokeswoman for the National Prosecutor's Office, said the samples have arrived at the UK's Defence Science and Technology Laboratory.
They are to be checked for traces of explosives, a process expected to take a few months.
More samples will be sent to laboratories in Italy and in Spain, after they were taken by Polish investigators who went to the crash site in western Russia.
Russia has refused to return the wreckage, saying it is needed for an ongoing investigation there.
Prosecutors are investigating whether anyone should face charges over the crash near a rudimentary military airport in Smolensk, Russia.
They plan to question Poland's prime minister of the time, Donald Tusk, who is now the president of the European Council.
Poland's ruling party is led by the late president's twin brother, Jaroslaw Kaczynski, who rejects findings by separate teams of Polish and Russian aviation experts who have concluded that the crash resulted from errors by the crew while attempting to land in dense fog.
The prosecutors have brought negligence charges against two officers of the now-dissolved regiment that was responsible for flying top officials.
They have also brought charges against two Russian flight controllers from Smolensk for allegedly giving the plane's crew poor guidance, although Poland has no legal power to bring them to trial.