The incident happened around 3:30 p.m. Tuesday at Smoke Hookah on West Avenue I, according to the Los Angeles County Sheriff's Department.
Homicide investigators are still trying to piece together what exactly happened, but it stemmed from some sort of argument between the victim and two men who entered the store.
One of the suspects took out a gun and shot the victim before they both took off running. Authorities have not confirmed what the fight was about or if it possibly stemmed from a robbery.
Authorities identified the victim as George Peter Al Hawara, 18, of Lancaster.
A family member told Eyewitness News that the victim was the son of the smoke shop's owner. He was working alone at the time.
"He's a baby. He didn't do anything. He had a whole life ahead of him, stolen by two demons," said the victim's cousin, Kristine Dabbas. "He didn't do anything. Please, if you're out there, turn yourself in. Turn yourself in. You took the most precious soul ever."
The victim's family said the smoke shop would remain closed Wednesday after the tragic shooting.
No arrests have been made. The investigation is ongoing.