A 78-year-old man was found dead in his Jaffa flat on Saturday afternoon. Police also found his injured wife, along with the couple's son, in the apartment.
Police arrested the son, 37, on suspicion of stabbing his father to death and attacking his mother. Magen David Adom said the woman was lightly hurt, and evacuated her to Holon's Wolfson Hospital.
The mother was quoted as saying that the son had "gone crazy" in the flat.
Police continued to investigate the circumstances of the incident.