A Gainesville man was formally charged Monday by a Hall County grand jury with aggravated assault, malice murder, felony murder and possession of a firearm in the commission of a crime. Authorities said Saul Merdez Castillo, 41, shot and killed Silverio Acosta, 46, at a June 16 soccer game at Tadmore Park in Hall County. The two men had a problem that went back to their native country of El Salvador, authorities said.