LOS ANGELES (AP) -- Fans of the San Francisco Giants and Los Angeles Dodgers have sustained one of the most passionate rivalries in American sport for more than a century, starting when both called New York City home and enduring through a cross-country move that placed them in California cities that -- fittingly -- also are rivals.
Visiting fans clad in their team's colors could always expect ridicule, and sometimes worse, in the stands. But now, for the second time in three seasons, serious violence outside the stadium has marred the rivalry.
Two years ago, Giants fan Bryan Stow suffered permanent brain damage when he was attacked in Los Angeles. This time, Dodgers fan Jonathan Denver died after being stabbed Wednesday night in San Francisco.
The latest incident has shaken and saddened fans of both teams.
"It's real unfortunate. It is just a game after all," said Brian Chew, a Giants fan from San Bruno who attended Thursday's game against the Dodgers.
"We have bigger purposes in life than just orange and black or blue and white," he added, referring to the Giants' and Dodgers' colors.
Police say Denver, 24, was with his father, older brother and two other people a few blocks from the Giants' ballpark when they exchanged words with some Giants fans.
"The back and forth, 'Go Dodgers!' 'Go Giants!'" San Francisco Police Chief Greg Suhr said. "And it deteriorated from there."
Denver suffered a fatal stab wound and Michael Montgomery, 21, of Lodi, was arrested on suspicion of homicide.
But Montgomery was released from custody late Friday night just after San Francisco District Attorney George Gascon said he was not yet ready to file charges and had returned the case to police asking for more evidence.
Montgomery was released from jail at about 9 p.m. pending further investigation and could be rearrested, Sheriff's Department spokeswoman Susan Fahey said.
Suhr had said Montgomery made "incriminating statements" that led to his arrest, but Gascon said not all witnesses have been questioned, and no independent witnesses have been interviewed in the stabbing.
"We are extremely concerned about the loss of life and want to make sure justice is served," Gascon said in a statement. "In order to meet our ethical obligation in charging this case, we must have a good faith basis to believe we can prove the case beyond a reasonable doubt."
Montgomery's father said his son told him he acted in self-defense after being attacked.
A second suspect was questioned and released by police earlier Friday.
"I just can't understand how, sporting event aside, society's gotten like this," Giants general manager Brian Sabean said Friday. "It's bizarre to me."
There was a moment of silence for Denver before the Dodgers hosted the Colorado Rockies on Friday night.
The killing happened more than an hour after a Giants-Dodgers game that -- beyond the rivalry -- had little consequence. Though the Giants are the reigning World Series champions, they muddled through a disappointing year while the Dodgers overcame a slow start to win the division.
Games between the two teams often have a playoff-like intensity, regardless of the teams' positions in the standings. "Beat LA!" is the crowd's refrain when the Dodgers play at the Giants' waterfront ballpark; "Giants suck!" cascades around Dodger Stadium.
Fans relish the demise of their rivals nearly as much as the success of their own team. The highlight of the Dodgers' 1993 season came on the last game of the year when LA drubbed the Giants 12-1. The loss knocked San Francisco out of the playoffs, despite 103 victories.
The rivalry extends from the field to the stands to the streets, and has long been mixed up in identity politics.
For much of the early 20th century, the Giants were "the darlings of New York City," favored by stockbrokers, politicians and the Broadway set, said John Thorn, Major League Baseball's official historian. The Dodgers, meanwhile, attracted support from immigrants and others outside the mainstream and were often identified as underdogs, even as they began to field powerhouse clubs in Brooklyn in the 1940s and 50s.
Both teams left New York following the 1957 season steeped in the joy of beating the other. Appropriate, then, that they relocated to California cities with clashing cultures.
To many a San Francisco native, Los Angeles is that place where shallow people transformed by plastic surgery dwell on whose car is better while they douse their lawns with water stolen from Northern California. If Los Angelenos think about San Francisco, it's a foggy bastion of we're-better-than-you snobbery clinging to a 1960s counterculture that has faded, save for the tie-dyed T-shirts of its tourist traps.