An official Home Office post-mortem conducted on the body of man discovered in a doorway in Hove could not determine the cause of his death.
An investigation began after officers were called to Brittany Road around 4.20am on Friday (August 20), where the remains of a man aged 59 were found at the entrance to his home.
Saturday's post-mortem brought no conclusive result, and police have said further tests will be carried out.
A 59-year-old man was arrested in connection with the death and has been released on conditional bail pending further enquiries.
Officers said the two men were known to one another.
Detective Inspector Simon Dunn commented:
“We are currently treating this man’s death as unexplained, and our investigation is ongoing.
“We would like to speak to anyone who may have seen or heard anything untoward in the area of Brittany Road and the Hove Kingsway, from around 8.30pm on Thursday (August 19) onwards.
"The road would have been relatively busy at this time with vehicles and pedestrians and anyone who has any information that could help with our enquiries is asked to get in touch.”
Reports are welcomed online, or by calling 101 quoting Operation Umbrella.
The independent charity Crimestoppers receives anonymous reports on 0800 555 111.
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