The Catholic Church in Poland is investigating church collaborators who assisted the communist-era secret police.

Church officials will work with historians to review secret police files which are now declassified, to find evidence of collaboration.

Father Robert Necek, spokesman for the Church in Krakow says, "The issue simply has to be investigated... we should not fear the truth."

According to the church, a commission was launched by the Archbishop of Krakow, Cardinal Stanislaw Dziwisz.

The latest round of investigations comes a year after the case of Father Konrad Hejmo, a Polish priest who admitted taking money from an alleged secret service agent while working at the Vatican, in Rome.