Grand Theft Auto: Liberty City Stories
The revelation was first disclosed during the mission Cam-Pain, in which Donald was dining on human flesh, which became a subject of concern for protagonist, Toni Cipriani, who advised him to get rid of the skeletons in his wardrobe, so as to secure the elections. In the end of the mission Love in the Run, Donald says the bodies will keep him company during the flight. It is assumed that he'll play with his food before eating it, which is necrophiliac in nature. Avery Carrington, his former preceptor, is likely to be a victim of Donald's sadistic nature and cannibalism.
Grand Theft Auto: Vice City
Soon after the disclosure, numerous players theorized that Donald's odd nature may exist in GTA Vice City. Although, these claims lack any authentic documentation, it is implied that Human Organs are supposedly purchased by Donald and he may be financing such activities in the city.