A mother appears to have committed suicide at the same time the body of her young daughter was found at their home, police said.
The body of the woman was found on a beach at the foot of Seven Sisters Cliff, Birling Gap, East Sussex, at 2.30pm yesterday.
The woman is thought to have fallen from the cliffs at about 2pm, according to Sussex Police.
At the same time, the body of her daughter was found in a bedroom of their house in Felpham, Bognor Regis, West Sussex.
She was found by police attempting to trace the owner of a car found abandoned at Birling Gap.
A police spokesman said only the mother and the daughter lived at the address and no-one else was being sought in connection with the deaths.
Det Ch Insp Nick Sloan, of Sussex Police, said: "This appears to be a tragic series of events.
"Our thoughts are with the family members at this very difficult time who are being supported by police family liaison officers.
"House-to-house inquiries are being conducted to establish the circumstances leading up to the child's death."
The spokesman added that post mortem examinations were due to be carried out on the bodies in the next 24 hours.
He said that the mother and child were not yet formally identified.