Farber was at the restaurant with a girlfriend when investigators say someone walked in, pulled out a gun and shot him several times.
"Our deputies were called to this location ... regarding a gunshot victim. An adult male was found shot to death inside of this business," said Lt. Dave Dolson, Los Angeles County Sheriff's Department.
Friends gathered at the place where Farber was shot, placing candles in memory of the young man. They said Farber not a gang member and that he was a good student with a good future and no one understands why this happened.
"I've got so many emotions that are running through me right now. That it's hard to describe ... It's like a nightmare," said Kenneth McGee, the victim's stepfather.
The family says Farber was a senior at Narbonne High School in Harbor City. He was a receiver for the school's football team. They say he had a college scholarship and was looking forward to starting classes in the fall.
"Play football ... that was his dream ... But like I always stressed to him, get the education, so you have something to fall back on," said Farber's step-father. "He was also going to take a course as far as being a firefighter. So he was getting ready to do all of these things and all this stuff was taken from him at a very young age."
Investigators were looking at surveillance video from the store to see what was caught on tape.
Farber's family says they won't stop until they find the man who murdered their son.
"To me, the person who did this is a coward ... To come in a place where a young man is eating and having dinner with a young lady and just to start shooting for no apparent reason. To me, that's a coward," said McGee.
Detectives say the restaurant is on a very busy street, so they believe someone must have seen the suspect when he left the restaurant.
Authorities believe the suspect has connections with a gang.
Anyone with information is asked to call the L.A. County Sheriff's Department at (323) 890-5500.