The police watchdog in South Africa is investigating the death of a taxi driver from Mozambique who was allegedly handcuffed to the back of a police van and dragged through the streets.

Video of the incident near Johannesburg, filmed by a bystander, has been shown in the local media.

The man in the footage was later found dead in a police cell, reportedly with head injuries, and a murder investigation has been launched.

Andrew Harding reports from South Africa.