Nicholas Campos, 34, of Pomona was arrested Tuesday on suspicion of assault with a deadly weapon and of being under the influence of alcohol and methamphetamine, police Sgt. Hector Rodriguez said.
The exact relationship between Campos and the man and woman has not been determined, but they are related, police said.
Authorities received a 9-1-1 call about 9 p.m. for a stabbing at a home in the 1800 block of Ninth Street, Rodriguez said.
Officers found a 60-year-old man suffering from a stab wound to the neck, Rodriguez said.
A 58-year-old woman was found at the home. Investigators learned she had been punched in the face.
The man and the woman were airlifted to a trauma center. Their condition has not been disclosed.
Officers identified Campos as their attacker, Rodriguez said. He had fled the area after the incident.
Officials learned the three were in the home when Campos and the woman started arguing.
Rodriguez said Campos then reportedly started punching the woman in the face.
When the 60-year-old man tried to stop the attack, Campos grabbed a knife and stabbed the man in the neck, police said.
Campos was found hiding a few blocks from the Ninth Street address and was taken into custody without any further incident.