An independent investigation is under way after the death of a man who collapsed in police custody.
Frank Morris, 47, from Widnes, died after being found unconscious in a cell at a custody suite in Runcorn, Cheshire, on 15 May.
He was taken to Warrington General Hospital but was pronounced dead.
The Independent Police Complaints Commission (IPCC) is to investigate the circumstances surrounding the arrest and detention of Mr Morris.
Tests inconclusive
The IPCC said Mr Morris had been arrested on suspicion of assault on 14 May.
He was found collapsed in his cell at 1000 BST the next day.
Although a post-mortem examination proved inconclusive, initial information suggested Mr Morris died from natural causes, the IPCC said.
Mike Franklin, IPCC commissioner for the North West, said: "Our investigation will be thorough and focus on all aspects of Mr Morris's arrest and detention to ensure the officers involved followed all the relevant policies and procedures."