Lt. Dan Rosenberg of the Los Angeles County Sheriff's Department said investigators found a hatchet at the scene.
James Lu was booked at the Sheriff's Department Temple station, where he is being held without bail, according to sheriff's jail records.
KTLA reported that investigators said the couple had been arguing before the attack. An adult son who was home at the time of the killing told deputies he heard his parents fighting and grabbed the hatchet from his father before calling 911.
Family members said Michelle Lu worked as a nanny six days a week and was home only on Sundays, according to KTLA.