Thames Valley Police is investigating the unexplained death of a woman in Buckingham on Saturday night.
Police were called to an address in Ryeland at about 7.15pm, after receiving a report that a 40-year-old woman had been found dead inside.
A post-mortem carried out on Sunday has proved inconclusive. Further tests are being carried out to determine the cause of death.
A 44-year-old man from Buckingham was arrested on suspicion of murder and has been released on police bail pending further investigation.
At this stage the death is being treated as unexplained.