Investigators say the victim was targeted and the public should not be concerned about a shooter aiming at people randomly.
The shooting happened at Fixins Soul Kitchen LA, a restaurant owned by former NBA star Kevin Johnson.
The shooter walked inside the restaurant just after 6 p.m. Tuesday and opened fire, killing a man in his 20s. A woman was grazed by a bullet.
Activists are urging anyone who may have information to come forward.
LA Live shooting: Man killed after gunfire erupts at downtown soul-food restaurant
One killed in shooting at LA Live restaurant in downtown, police say
"We're saying if you know something say something," said Lawanda Hawkins, of Justice for Murdered Children. "You need to let law enforcement or Crime Stoppers know what happened. Because we know someone besides the shooter knows what happened here and my heart and prayers go out to the family of the murdered victim."
Eyewitness News reached out to the restaurant owner but Johnson declined to comment.
The restaurant, however, posted a statement on X, reading in part, "At Fixins, community is our core. Saddened by the recent incident at our LA spot, our hearts go out to the victim's loved ones. Rest assured, immediate security measures are in place to ensure your satisfaction and safety. Thank you for being part of our resilient community."
Los Angeles Police Department Chief Michel Moore said the department is providing extra patrols around the L.A. Live area.
"The nature and manner and place that it occurred - how terrifying that can be to the public," Moore said. "We've reached out in speaking with principals at L.A. Live, as well as with Kevin Johnson. We extend to them our every assurance that we will have added patrols in those areas while we conduct a very aggressive investigation to identify the individual responsible for this."
"There's a number of leads that we have, physical evidence on scene and other things that I'm not prepared to talk about, but I have every confidence that we will identify what has occurred here, who's responsible and bring them to justice."