An investigation has been launched into the police killing of two suspected robbers during a hostage drama in Petrusburg in the Free State, the Independent Complaints Directorate (ICD) said on Thursday.

The ICD was investigating a case of death as a result of police action, spokesperson Moses Dlamini said in a statement.

National Police Commissioner Bheki Cele commended the Special Task Force for killing the two hostage takers on the Abrahamskraal Road at Bainsvlei on Tuesday morning.

On Monday, the robbers attacked and tied farmer, Flip Kotze (60) to a pole on his farm Uitvlug and fled with his bakkie, firearm and a cellphone. Kotze untied himself and alerted his neighbours.

Therobbers then hijacked 50-year-old farmer, Gerhard Venter, and an unidentified relative. The relative managed to get out of the bakkie and fled to a nearby police station. The two held Venter hostage and threatened to kill him if police did not back off.

Police stopped the robbers on the route to Bloemfontein via Bainsvlei. Police negotiators tried without success to convince the men to release Venter from 1pm on Monday until the early hours of Tuesday morning. Police snipers then shot both thieves in the heads. Venter was not hurt.