PROSECUTORS BEGAN closing arguments Monday in the kidnapping and assault trial of Winnie Mandela, arguing her alibi might be false and that the testimony of at least one of her accusers was credible . . . BANDITS POSING as police stopped an armored security van on a highway near Florence, Italy, early Monday and stole 550 pounds of gold ingots after wounding a guard, police said . . . THREE ARMED ROBBERS held up Macao's largest casino Sunday and injured three people in a hail of gunfire as they escaped with more than $750,000 - in gambling chips.