Police on Tuesday responded to the second floor Sherman Avenue apartment that 27-year-old John Ugarriza shared with his 73-year-old granddad, Jesus Ruiz.
Ruiz was pronounced dead at the scene. Police say he was stabbed multiple times with a knife.
Ugarriza is held on $250,000 bail, charged with murder and weapons charges.
It's not known if he has a lawyer.