The man was arrested today (July 3) on suspicion of murder and remains in police custody.
Usmaan’s family has been made aware of this and are currently being supported by specially trained officers.
A post-mortem examination held on Thursday, June 15 confirmed his cause of death as sharp force trauma.
At 4.16pm on Tuesday, June 13, officers on patrol in Thornton Heath were made aware of a man who was injured at the junction of Melfort Road and Sandfield Road.
Mahmood was found with stab injuries and was taken to hospital; he died there in the early hours of Wednesday (June 14).
Any witnesses or anyone who can help are asked to call police on 101 or tweet @MetCC quoting CAD 5777/13Jun.
Detective Chief Inspector Mike Nolan from the Met’s Specialist Crime said: “My officers are continuing to provide support to Usmaan’s family at this unimaginably difficult time for them. Getting justice for them and for Usmaan continues to be our priority.
“This morning we made an arrest in connection with Usmaan’s murder. However, I still need to hear from anyone who may have information about what happened.
“A young man has lost his life and it is imperative we identify those responsible. Londoners don’t want violent criminals in their communities and we must work together to remove them from our streets.
“We believe Usmaan was stabbed inside Thornton Heath Recreation Ground and we are appealing for anyone who may have been at the park at the time of the incident to come forward with any information.
“Please do the right thing and call us with anything that could assist our investigation and bring his killer to justice.”
