Los Angeles police said gunshots were reported in the area of Kensington Road and Echo Park Terrace about 1:40 a.m.
About 20 minutes later, the father of the victim said he went outside to check on his son because he heard him arguing with someone prior to the gunshots. The victim, Etsael Cardenas Jr., was found unresponsive. Paramedics transported Cardenas to a hospital, where he died a short time later.
Family members said Cardenas had been sitting in his car listening to music, as he often did.
"Nobody saw nothing. They heard it, but we don't know who it was," said the victim's sister, Daisy Cardenas. "My dad heard the gunshot, reacted to it, went out looking for him (because he) noticed he wasn't home, and they found my brother dead in the car."
Police said Cardenas was shot twice on the side of his chest.
"He was our only brothers," said Daisy Cardenas. "We're four girls and he was the one to take care of us, so this is really hard for us."
Police are searching for suspects.
Investigators are looking for witnesses. Anyone with information is urged to call the LAPD's Rampart Division at (213) 484-3400.