On 1 July, Mohammed Amar Salem, 29, threatened PC Reuben Pace, PC Nigel Apap and PC Brendon Borg.
The man was also found guilty of breaching the peace, possessing heroin and stealing a mobile phone worth over Lm100.
Magistrate Joseph Apap Bologna presided over the court.
Inspector Josric Mifsud prosecuted while Dr Leo Bencini appeared for the accused.