The 15-year-old boy was arrested on suspicion of murder late on Saturday, 1 January. He was taken to a south London police station where he remains in custody.
Detectives launched a murder investigation after police were made aware of an assault in Ashburton Park, Croydon shortly after 19:00hrs on Thursday, 30 December.
Officers attended and found 15-year-old Zaian Aimable-Lina suffering from stab injuries. Officers immediately provided first aid prior to the arrival of the London Ambulance Service.
Despite their efforts, Zaian was pronounced dead at the scene at 19:36hrs. His family have been informed and are being supported by specialist officers.
On Friday, 31 December, a 15-year-old boy [A] was arrested on suspicion of murder. He was taken to a south London police station and later released on bail to a date in late January.
A post-mortem examination was held on Saturday, 1 January and gave cause of death as a stab wound to the heart.
Anyone with information is asked to call the incident room on 020 8721 4622, or police via 101 quoting reference CAD 5443/30Dec21. To remain anonymous, contact Crimestoppers on 0800 555 111.
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