At 11:00 p.m., an elderly husband and his wife were accosted in the entrance to their apartment building by the defendant, who was armed as well as masked. The defendant ordered the couple to take him into their apartment. After they entered the apartment, the defendant forced the wife to bind and gag her husband and then to open a safe with contained a diamond necklace. The defendant then tied her up and fled with the necklace. He was apprehended by apartment building security guards. Before the guards could return to the apartment, but after the defendant was arrested, the husband, straining to get free, tripped and fell, causing him to suffer a seizure from which he died. The defendant is guilty of: