Boxing legend Julio Cesar Chavez's brother, Rafael, was murdered in Mexico during a botched armed robbery ... local authorities announced Monday.
According to a Sinaloa state prosecutor, two men entered Rafael Chavez's Culiacan home Sunday night and demanded money. One of the men was armed.
During the robbery, Chavez resisted and was shot and killed in front of his family.
Julio Cesar Chavez is widely considered one of the most iconic Mexican boxers of all time ... and Julio Jr. -- Rafael's nephew-- fought Canelo Alvarez last month.