A taxi firm controller who was knocked unconscious in an attack at his office has died in hospital.
West Midlands Police launched a murder investigation after the 37-year-old victim died on Sunday, two days after officers were called to Embassy Cars on Oliver Street, Birmingham.
Detective Inspector Paul Joyce said: "No arrests have been made as yet but inquiries are moving at a swift pace and I am appealing to anyone who can help the investigation to get in touch.
"We are still trying to understand what happened but we are led to believe that a customer visited the taxi office in Nechells after being picked up earlier in the evening.
"There was some sort of disagreement and he became aggressive and assaulted the member of staff.
"We are liaising with the man's family following their tragic loss and we are determined to find the man responsible as quickly as possible."