Prosecutors decline to charge man arrested in Dodgers fan stabbing SAN FRANCISCO (Reuters) - San Francisco prosecutors on Friday declined to file charges against a 21-year-old Northern California man arrested in the stabbing death of a Los Angeles Dodgers fan during a fight after a baseball game, saying he may have acted in self-defense. Michael Montgomery of Lodi, California, was arrested on Thursday along with a second suspect a day after the fatal stabbing of Jonathan Denver, the 24-year-old son of a Dodgers security guard, outside a bar just blocks from the San Francisco Giants stadium, AT&T Park. Police who took the two men into custody said the altercation began as a shouting match between fans of the rival Dodgers and Giants baseball teams. The second suspect, who was not identified by authorities, was released from custody on Wednesday without being charged. "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," San Francisco District Attorney George Gascon said in a statement. "Additionally, in California, it is the people's burden to prove beyond a reasonable doubt that the defendant did not act in lawful self-defense," Gascon said. It is vital for our office to have independent corroboration of the incident in order to meet our ethical obligation to charge this case. It was not immediately clear if Montgomery had been released on Friday evening. Under California law police can only hold him for 48 hours without charges. "My office extends its deepest and most heartfelt condolences to Jonathan Denver's family," Gascon said. We are extremely concerned about the loss of life and want to make sure justice is served. The prosecutor suggested in his statement that charges could still be filed against Montgomery if further evidence against him was developed. "The San Francisco Police Department has provided us an initial investigation," he said. However, not all witnesses have been interviewed, nor have any independent witnesses of the incident been interviewed. We have requested this and other evidence be collected before we can make an assessment on whether charges should be filed. Denver's death follows a 2011 attack on Giants fan Bryan Stow, who was badly beaten in a Dodger Stadium parking lot in an attack that raised concerns about stadium security. Writing by Dan Whitcomb; Editing by Lisa Shumaker