A man has been bailed by detectives investigating the death of a man on Upper Clapton Street in Hackney.
The 26-year-old man was arrested after attending an east London police station on Thursday, 5 April.
He was interviewed by homicide detectives from City of London Police and bailed to a date in late April pending further enquiries.
Recognising the current demand on the Met's Homicide and Major Crime Command (HMCC) - with new and existing investigations - City of London Police approached the Met to offer assistance.
City officers are investigating this murder, supported by colleagues within the HMCC. The investigation is being led by Superintendent Lee Presland, from City of London Police and a former Met officer.
The Met routinely works closely with other forces, especially its neighbouring forces - which include City of London Police - on a variety of crime prevention initiatives such as Operation Sceptre to tackle knife crime, and we welcome the considerable expertise City officers bring.
Police were called at 16:27hrs on Wednesday, 4 April, to a bookmakers on Upper Clapton Road, E5, after reports of a man found unconscious.
Officers attended with the London Ambulance Service (LAS) and London's Air Ambulance.
Despite the efforts of medical staff, the 53-year-old man was pronounced dead at the scene.
His next of kin has been informed and a post-mortem examination commenced at Poplar Mortuary on Friday, 6 April which is ongoing. He is yet to be formally identified.
The victim is believed to have been involved in an altercation with another man who then left the scene. Enquiries are ongoing to establish the exact circumstances of this incident and any possible motive.
Anyone with information is asked to contact police via 101 or Crimestoppers anonymously on 0800 555 111.