Officers were called to reports of a young person at risk in Green Wrythe Lane just before 8.40pm on August 10.
London Ambulance Service crews also attended and a man was found injured.
He remains in hospital where his condition was confirmed as neither life threatening nor life changing.
His next of kin are aware.
Police enquiries are ongoing.
A spokesperson for Metropolitan Police said: “Officers are working to establish the circumstances around what happened.
“If you have any information which may help, please call police on 101 with the reference 6457/10Aug.”
