The family of a man who died in police custody have said they are "shocked and devastated".
Simeon Francis, 35, died in a cell in Torquay police station on 20 May after being arrested in Exeter.
Mr Francis's siblings said they wanted "answers as to why he died in these circumstances".
A preliminary post-mortem examination did not find a cause of death, the Independent Office for Police Conduct (IOPC) said.
Bishop Dr Desmond Jaddoo, who is supporting the family, called for a "thorough and transparent" investigation from the IOPC, and said he expected "the utmost co-operation from Devon and Cornwall Police" .
A family statement added: "The news of the death of another black man whilst in police custody raises again the concerns regarding the disproportionality of black people dying in custody."
Mr Francis, who has a 10-year-old child, moved to Torquay from Birmingham 16 years ago.
He was arrested at about 00:45 BST on 20 May in Cowley Bridge Road, Exeter and taken to Torquay before being booked into custody at about 03:00, the IOPC said.
Police said paramedics were called after Mr Francis was found "seriously unwell" in his cell in the afternoon.
The IOPC said an ambulance crew pronounced him dead at about 18:00.
Mr Francis's father said: "We are shocked and devastated at the sudden loss of my beautiful son Simeon.
"As a father, I would never have expected to be dealing with the death of a child in such circumstances.
"The family and I are seeking answers as to what happened to Simeon."
Devon and Cornwall Police said it was "co-operating fully" with the inquiry.
Bishop Jaddoo added: "The family's request is a simple one - why is Simeon dead?"