The youth had suffered from severe bleeding and shock, the report by the judicial Medical Officer (JMO) had said.
The youth died following an altercation with the police which took place when then police visited a house where a party was held.
The police headquarters had later temporarily transferred 21 policemen over the incident.
The former Embilipitiya Assistant Superintendent of Police (ASP) DWC Dharmaratna was arrested over the death of the youth. (Colombo Gazette)