A CFMEU administrator sent corruption investigators away, only to later sack a top figure.
Two teams of investigators with experience in integrity were assembled to uncover corruption in the union, but were quickly disbanded.
According to three confidential sources, CFMEU administrator Mark Irving KC failed to enact advice to seek more powers from the federal government to deal with wrongdoing.
One source said Irving was concerned that seeking more powers could risk reviving calls for the coalition's Australian Building and Construction Commission.
Former AFP officer Chris Craner was recruited to help investigate wrongdoing at the CFMEU, but the investigation was abandoned, leaving serious misconduct allegations untouched for months.
Author's summary: CFMEU corruption investigation was abandoned.