"If it can happen to us, it can happen to anyone," said Angelica Sandoval, the victim's daughter. "My father was innocent."
Luis was out for his daily bike ride around 5:00 a.m. when he was shot.
Investigators say at this point they don't know if Luis was caught in the crossfire or targeted to eliminate him as a possible witness.
Luis was shot once in the abdomen. He managed to ride his bicycle back home and call for help. He passed away after spending four months in the hospital, fighting to survive.
The 71-year-old grandfather was one of the victims of graffiti taggers. Investigators say taggers are growing increasingly violent.
"They start out as taggers ... then their tagging starts getting crossed out. Then, they become defensive and start tagging up in other people's territory and pretty soon taggers are just another word for gang member," said Lieutenant Gill Carrillo, Los Angeles County Sheriff's Department.
Investigators say they know which crews were involved in Luis Sandoval's murder, but no one has been willing to identify specific suspects.
The County Board of Supervisors is now offering a $25,000 reward, hoping to crack the case.
Luis's family says all they want is for someone to finally do the right thing.
"Anyone can take a life. But, true bravery and courage comes from giving life and letting someone live. And this is very cowardly," said Angelica Sandoval.
Anyone with information should call the Los Angeles County Sheriff's Department's Detective Bureau at (323) 890-5500.