Camberwell
The child was grabbed by an unknown man in Camberwell, south-east London, in October.
Two men aged 34 have been detained.
Police say there was a "possible disturbance" before the fall.
Witnesses heard a teenager cry 'help, help' before the four young men were stabbed.
The musician was stabbed to death in Camberwell.
Kenneth Umezie will appear before magistrates on Wednesday.
The pair are in hospital with non life-threatening injuries.
Two men arrested on suspicion of murder.
It closed more than a century ago.