TWO men — one a member of the presidential protection unit — were arrested on Friday when they allegedly tried to exchange firearms for gold and diamonds, police said on Tuesday. Investigating officer Senior Superintendent James Erasmus said one of the guns allegedly involved had been stolen from a safe in Mandela’s Johannesburg home. The gun was reported missing in July. The other three firearms were allegedly removed from another safe belonging to the unit. Erasmus said the two men will be charged with illegal possession of a firearm, and pending an investigation will also be charged with the theft of the firearms.