The shooting happened just after 10 p.m. Saturday in a residential neighborhood near East Camellia Drive and Peachtree Lane, according to the Covina Police Department.
16-year-old boy shot and killed at Covina pool party, police say
A memorial for the victim, identified by family members as Joel Mercado, continues to grow with more candles and flowers as community members and loved ones mourn the teenager.
Mercado's sister told Eyewitness News he was at the party with a friend, but there are still many unanswered questions.
"It's just hard because we don't know what happened. We weren't there. We didn't get to say any goodbyes, we didn't get to be there with him at all. He was alone... and I think that's just what's really hurting... all of us," said Adrena Nunez. "He didn't have any family. We're all about family. We have a big family and he was just all alone."
Police have not released information about what led up to the shooting, a suspect or any arrests.
Anyone with information about the deadly shooting is urged to contact Covina police.