Master Oscar Nabikhwa was playing with other children on the balcony of their apartment when he slipped and fell to the ground floor.
Police said young Oscar had returned home from school before venturing out with other children on Monday evening, 17 April, when the incident occurred.
His mother, who was in the house at the time, told police she was told by other children that her son had fallen from the balcony.
“I rushed downstairs where I found him bleeding from the head after the fall. My neighbours helped me take him to the hospital where he was pronounced dead,” read part of the police report.
Police visited the scene after the incident as part of their investigation.
They declared it an accident but added that an inquest had been opened to reach a conclusion.
Nairobi police chief Adamson Bungei urged parents to be careful and keep an eye on their children, saying incidents were likely to happen as children stayed at home during the school holidays, which began this week.
At the same time, he urged developers to put safety measures on structures to ensure the safety of vulnerable people, especially children.
A post-mortem examination of the body is planned as part of the investigation into the death.