Amateur side Brumadinho was playing against Amantes da Bola - which literally translates as 'Lovers Of The Ball.'
League president Valdenir de Castro claimed Murta was kicked and slapped after Amantes da Bola subs and the manager invaded the pitch to demand a red card for a rival team player.
Referees' association boss Giuliano Bozzano said the official felt threatened and went to look for the weapon to defend himself.
He was due to undergo a psychological assessment later today and could face suspension or a permanent ban.
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