A post-mortem was under way in Christchurch after the body of a woman was found in the Port Hills early on Wednesday morning.
Police believe the body is that of Kerry Leigh Downey, 52.
Detective Senior Sergeant Grant Wormald says Ms Downey was last seen in Riccarton on Monday evening.
Mr Wormold says police officers investigating Ms Downey's death are focusing on the movements of her car.
Ms Downey's red Suzuki Alto car was found on Wednesday morning in Neville Street, Spreydon.
Police say a vehicle fitting the same description was reported being driven erratically on Monday night.
Meanwhile, a man has appeared in Christchurch District Court charged with theft of property believed to have been in the dead woman's possession and has been remanded in custody.
Second missing woman
Meanwhile, a search is being made of the Avon River at Avonside in Christchurch as concerns grow for a woman who disappeared on Monday.
Police say Joan Lorraine Catlow, 39, left her Dallington home about midnight wearing only a blue satin nightdress and a towelling robe. They say the weather was very cold and wet.
Residents in the Gayhurst Road area near where she lived are being asked to check their garages and sheds in case she took shelter there.
Detective Senior Sergeant David Harvey says police have had a good response to appeals to the public for help, but still need more information.
Mr Harvey says they are not considering foul play at present.
Ms Catlow is described as European, of slim, slight build and with long dark hair.
Her family says her disappearance is out of character.