Investigations have been launched following the discovery of 18 dead migrants inside a lorry in Bulgaria. This footage shows the police cordon surrounding the vehicle which was abandoned on a highway near the capital, Sofia.Around 40 migrants had been inside the truck, according to preliminary information from the Interior Ministry. Survivors were brought to hospitals for emergency treatment.It is believed that those who passed away died from suffocation. The driver was not inside the lorry when it was discovered. Source: PA