Sungai Buloh District Police chief Supt Mohd Hafiz Muhammad Nor said the police received information about the incident at 4.28 pm and personnel found the child dead upon arriving at the scene.
He said the preliminary investigation involving the victim's parents, who were in their 30s found that the family was sleeping when the incident occurred.
"When the victim's mother woke up, she found that her youngest son was on the edge, outside of an open living room window, but did not have time to get the victim before he fell," he said in a statement yesterday.
Mohd Hafiz said the boy was pronounced dead by medical officers at the scene and the cause of death was still under investigation.
"A sudden death report (SDR) investigation paper has been opened with regard to the incident and the victim's parents will also be interviewed soon," he said.
He said anyone with information regarding the incident could contact any nearby police station or the Sungai Buloh District Police Headquarters at 03-61561222 to help with the investigation.
-- BERNAMA
