looking for help finding his son's killer. Incredibly, his son lost his life because of a rivalry between fans of the dodgers and the giants. And this isn't the first case. In california tonight,... See More
looking for help finding his son's killer. Incredibly, his son lost his life because of a rivalry between fans of the dodgers and the giants. And this isn't the first case. In california tonight, here's abc's aditi roy. Today, I'm making a plea to the public, asking that anyone who may have witnessed the incident, to come forth. Reporter: A father makes a plea for information in his son's death. It was supposed to be a family night at the ballpark. 24-year-old jonathan denver was stabbed to death near at&t stadium after police say his group got into an argument with a group of giants fans after the game. There was a back and forth about the giant/dodger rivalry, which deteriorated into a physical fight. Reporter: San francisco police arrested 21-year-old michael montgomery, then released him saturday night, citing insufficient evidence. It's not the first time violence erupted from dodgers/giants rivalry. In 2011, giants fan bryan stow suffered a traumatic brain injury after being beaten by two men dressed as dodgers gear following a game between the two teams in los angeles. At thursday night's giants game against the dodgers, a moment of silence for denver. His father asking for answers. The giants released a statement, expressing sadness over denver's death, adding, there is no place in your community for this type of violence.
This transcript has been automatically generated and may not be 100% accurate.