The man murdered in cemetery has been named by police.
Peter Charles John, 54 of East Acton Lane, Ealing, was found unconscious with neck injuries in City of London Cemetery, North Boundary Road.
A murder investigation was launched after police were called at 2.17 pm on Wednesday.
No arrests have been made and police say they are keeping an open mind about the motive.
An incident room is open under Detective Chief Inspector Chris Jones, Homicide and Serious Crime Command (HSCC).
Anyone with information is asked to call the incident room on 020 8345 3734, or to remain anonymous, call Crimestoppers on 0800 555 111.