A man has been arrested on suspicion of murder after a 35-year-old man died in hospital after a possible assault.
Police were called to an address in Grays, Essex, after a man who was taken ill at about 03:30 BST on Thursday.
A 38-year-old man from Tilbury was arrested by officers and is in police custody for questioning.
Police appealed for witnesses to a disturbance at an address in Parsonage Road overnight between 12 April and 13 April.
An Essex Police spokesman said: "We are investigating the circumstances surrounding his death as we believe he may have been assaulted in the days beforehand."
Anyone with information is asked to call Essex Police.