A post-mortem examination on a man found collapsed in a street has proved inconclusive, police say.
The man in his 50s was discovered in Coventry Road, Yardley, Birmingham, at about 22:20 BST on Saturday and died after arriving at hospital.
Further tests are required to establish the cause of death, West Midlands Police has said.
A 28-year-old man held on suspicion of murder has been released on bail while investigations continue.
On Sunday, officers said following inquiries it was believed the man who died had been assaulted before he was found.