The Morris Tribunal has been shown a letter from Adrienne McGlinchey to Garda Commissioner Pat Byrne in which the former complained of garda intimidation.
Ms McGlinchey wrote to Mr Byrne in July 2001 accusing gardai of shouting at her in the street because she was helping the internal inquiry established to investigate alleged garda corruption in Co Donegal.
Ms McGlinchey is a key witness in the Morris Tribunal, which was established following the findings of the internal Carthy inquiry.