Specialist crime detectives are continuing to investigate following a shooting in Sydenham during which a 25-year-old man died.
Shots were subsequently heard and firearms officers also attended along with the London Ambulance Service.
A 25-year-old man was found with gunshot wounds - he died at the scene at 3.50pm.
Next of kin have been informed but he is yet to be formally identified.
No one else was injured during the incident.
Detective Chief Inspector Richard Leonard said: “We are still in the early stages of the investigation and our enquiries into how the man came to be fatally injured continue.
“However, one hypothesis is that the man unintentionally discharged a firearm resulting in his fatal injury.”
One man has been arrested in connection with the investigation and remains in custody at a south London police station.
Anyone with information about the incident is asked to call police 101 quoting CAD 4860/8Sept or the independent charity Crimestoppers on 0800 555 111.
They do not ask your name and cannot trace your call or I.P address.