Aaron Michael Hammer appeared briefly in Superior Court but Judge John J. Cheroske postponed his arraignment to Sept. 23 at the request of the defense. He remained held without bail.
Hammer, 24, of Compton, is accused in the shooting of Yetunde Price, 31, as she sat in a sport utility vehicle early Sunday with a companion, Rolland Wormley, 28. An assault rifle and shell casings were found at the scene.
Authorities initially reported she was shot in the chest, but a coroner's spokesman said Tuesday an autopsy showed she died of a gunshot wound to the head.
Hammer also was charged with using and possessing a firearm. If convicted of all charges, Hammer would face life in prison with the possibility of parole.
Hammer has ties to a Compton street gang but is not a member, authorities have said without elaboration. He has convictions for check forgery and commercial burglary.
Authorities declined to say whether Hammer was the gunman who fatally shot Price. As many as three other suspects are being sought in the case, Deputy Richard Pena said.
Activists and residents raised candles in Price's memory Monday night at an anti-violence rally in Compton, a crime-plagued city southeast of Los Angeles.
Price, a registered nurse who owned a beauty salon, was one of five sisters who spent their early years in Compton. Price, a mother of three, also served as a personal assistant to her famous half sisters, who moved to Florida with their parents when they turned pro as teenagers.
Sheriff's investigators said Price and Wormley got into a dispute with a group of residents in front of a home in an area known for gangs and drugs.
The prosecution did not release any information on a possible motive for the killing. Authorities said they had no indication that Price, who lived about 40 miles away in Corona, was involved with drugs or gangs.
Wormley drove the wounded Price to his relative's house in neighboring Long Beach and called 911. Price was taken to a Long Beach hospital, where she died.
Wormley's sister attended Hammer's court hearing and afterward disputed investigators' account of the shooting. She said the pair were "just driving through" Compton at the time.
"There was no confrontation," said Carmelle Wormley.
Richard Williams, father of Serena and Venus Williams and stepfather of the victim, also attended the hearing. He left without comment.
By Jeremiah Marquez