Six people, one of them a 7-year-old girl, were wounded in the shooting Saturday at Peregrine Park, police said. Investigators have said they believe the shooting was gang-related.
"The suspects fired at a specific group in the party, and subjects from the party shot back at the suspects," Officer Michele Gigante, a police spokeswoman, said Sunday.
Tiffany James of Sacramento told the Sacramento Bee the dead man was her cousin, Jacoby James, 28. She said James made T-shirts and sold them online.
Her cousin was at the park because of the birthday party, Tiffany James said, describing him as a "loving father." She believes he was not a target of the shooting.
"I don't think it was meant for him," she said. "He was very humble, and he just lived with his family."
Investigators said between 20 and 30 adults and 30 children were at the party at about 5 p.m., when a vehicle pulled up and stopped and several men got out and opened fire. Some of the partygoers returned fire.
The group that first began shooting left. Police said they were trying to use security footage to track the vehicle, and asked any homeowners in the neighborhood who have cameras set up to get in touch.