WARSAW -- Oscar-winning director Andrzej Wajda is to make a film on the 1940 Katyn massacres, one of the earliest and most infamous mass-shootings of prisoners during World War II where 22,000 Polish officers were shot by Soviet police.

Wajda, who spent several years looking for a text on which to base his film commissioned writer Wlodzimierz Odojewski to compose a novel on the massacre which already features in his earlier work, AFP said.

"The film's hero is based on a real person who worked as an activist for the communist youth before the Second World War," Odojewski told the ***Rzeczpospolita*** daily Friday.

"A (Polish) officer during the war, he found himself held in the German camp in Murnau while his brother was killed in Katyn. After the war he was put in charge of the official investigation into Katyn. It came as a great blow to him to discover that rather than the Germans, it was Russians from the communist secret service who were implicated," writer Odjewski said.

Under the German-Soviet non-aggression pact (Ribbentrop-Molotov), Poland was invaded by Nazi Germany on September 1 1939, followed two weeks later by the Red Army.

The communist secret service then captured and executed Polish officers. The first open graves were found at Katyn in April 1943 by Germans.

The former Soviet Union, who had long accused the Nazis of having committed the massacre, finally admitted responsibility at the end of the Gorbachev era.

In October 1992 Boris Yeltsin handed over massacre-related documents signed by Stalin to then Polish president Lech Walesa.

Wajda, 76, hopes to start filming in the autumn, according to ***Rzeczpospolita***. He was awarded an honorary Oscar in 2000.