Per California Tenant Law,

if a prior occupant of the rental unit died in the unit within the last three years, the owner or the owner's agent must disclose this fact to a prospective tenant when the tenant offers to rent or lease the unit. The owner or agent must disclose the manner of death, but is not required to disclose that the occupant was ill with, or died from, AIDS. However, the owner or agent cannot intentionally misrepresent the cause of death in response to a direct question.