Fears were growing for an 82-year-old woman who went missing in Cambridgeshire on Monday, police said.
Sally Middleton was dropped off at a bus stop at Werrington near Peterborough on Monday morning.
She was spotted on CCTV in Queensgate Bus Station an hour and a half later but has not been seen since.
Officers have been searching areas of Bretton and Werrington and urged anyone who may come across Mrs Middleton to stay with her until they arrive.
Inspector Leigh Allman said: "We are following up several possible sightings and I would urge members of the public to continue to call us with any information."
Mrs Middleton is 5ft (152cm) tall and slim.
She has black, greying collar-length hair and brown eyes.
She was last seen wearing light-coloured trousers and a light-coloured check coat over a dark top and black shoes.