A man has been freed on police bail after being arrested on suspicion of murdering a woman whose body was found by a colleague who was due to take her to work.
Police and paramedics were called to Cherry Tree Cottage in East Ashling, near Chichester, West Sussex, on Monday after 44-year-old Debbie Levey was discovered dead in the house.
A 45-year-old man from Selsey, who was known to Ms Levey, was arrested on suspicion of her murder and released on conditional bail until 21 February, pending further inquiries.
Sussex Police said that a post-mortem examination carried out at St Richard's Hospital failed to find a cause of death, and further tests will be conducted.
Detective Chief Inspector Ian Pollard, of the Surrey and Sussex Major Crime Team, who is leading the investigation, said: "While initially it was thought that we were dealing with a sudden death, officers became increasingly suspicious of the circumstances.
"At this stage our inquiries lead us to believe that this may not have been a natural death and a murder inquiry was launched on Monday."
Police said the last time Ms Levey was seen alive was at her home at 12.30pm on Sunday.
Officers appealed for information from anyone who saw her or was in contact with her after that time up until Monday morning.
People were also being asked to come forward if they saw a blue Vauxhall Vectra parked in a small lay-by across the road from Cherry Tree Cottage on Sunday afternoon or early that evening.
Ms Levey was employed at the Leaholme care home in Chichester, which is run and managed by Places for People.
A Places for People spokesman said: "We are all deeply saddened by the death of Debbie, and our thoughts are with her family and friends at this very sad time.
"As the manager of one of our care schemes she displayed so much passion and warmth when caring for others.
"We have trained staff on site to provide emotional support and assistance to colleagues, and we are also working with the police as part of their ongoing investigations."
Anyone with information is asked to call Sussex Police on 101, quoting Operation Dive, or Crimestoppers, anonymously, on 0800 555 111.
Relatives of Ms Levey, who had a daughter, paid tribute to her tonight.
Speaking on behalf of the family, her father, John Etherton, said: "We are all absolutely devastated by this terrible news.
"Debbie was a most caring and compassionate person, who worked in a series of caring professions.
"We all loved her deeply. She will be very much missed by her family, and also by colleagues and her friends and neighbours."