Polish team examining jet debris from 2010

WARSAW, Poland, July 24 (UPI) -- A Polish prosecutor said he is conducting a follow-up investigation of jet debris from the crash that killed President Lech Kaczynski three years ago.

The prosecutor and four experts will examine seat fragments from the debris until the end of next week, RIA Novosti said.

The Russian-made jet, carrying Kaczynski, his wife and top officials, crashed in heavy fog near Smolensk, Russia, in April 2010.

The group was flying to Russia to mark the 70th anniversary of a massacre of thousands of Polish officers by Soviet secret police.

All 96 people on the plane died in the crash.

Russian and Polish investigators carried out a joint investigation last spring in a response to a claim a bomb could have been responsible for the crash.

Investigators found no traces of an explosion.

But the head of Warsaw's district military prosecutor's office, Ireneusz Szelag, said the research was insufficient to rule out the possibility of explosive charges, RIA Novosti said.

The Interstate Aviation Committee in Moscow said in its report the Polish flight crew was to blame for the accident, while Poland, in its investigation, blamed Russian air traffic controllers.