Interviewed after retirement, van der Merwe says that he enjoyed initial training. In 1961 he was posted to Standerton in charge of administration of the new headquarters. From 1963 to 1966 he worked in an administrative role at Security Headquarters. From 1966 to 1970, he commanded a border post at the South Africa-Lesotho border. When interviewed, he said that the Lesotho government under Leabua Jonathan enjoyed far less support than his superiors thought. In 1970, he was posted to the Security Branch in Bloemfontein; he eventually took command throughout the Orange Free State. Interviewed, he claimed to have helped to prevent unrest during the Soweto uprising in the Free State due to his close relations with parents of schoolchildren. From 1979 he was then posted to South West Africa, now Namibia, which was then illegally under the control of the South African authorities. He recalled in an interview that he had “almost unlimited legal powers” in Namibia due to the co-operation of the Administrator General; recalling his time in Namibia, he said that he “would not miss…for all the money in the world”.
Time in the Security Branch and as Commissioner
In 1983 he was posted to Pretoria, where he rose initially from second in charge of the Security Branch to Head of Security, before becoming Deputy Commissioner and then in 1990 Commissioner of the South African Police. In 1985 he had a report sent to the minister requesting further powers, but was rebuked by Louis le Grange, then Minister of Police. In van der Merwe's view, the apartheid government's response to the United Democratic Front was hobbled by several factors: arrestees had the right to have the evidence against them furnished before the court, which would frequently identify informers, and it was very difficult to detain children who participated in the unrest. He says that at that time “the main drive for us as a Security Branch to protect our people” and to maintain law and order. Despite the handover of power from the National Party to a non-racial government of national unity under the provisions of an negotiated interim constitution, van der Merwe remained Commissioner until 1995.
Retirement and application for amnesty
In 1995 van der Merwe resigned from the police force. The Mail & Guardian reported that he was pressured to resign by the then Safety and Security Minister Sydney Mufamadi over accusations that he was obstructing investigations into other apartheid-era officers and alleged so-called Third Force activity. With several other security policemen, van der Merwe successfully applied for amnesty from the Truth and Reconciliation Commission for various offences. However, in 2007, van der Merwe along with Adriaan Vlok, an apartheid-era Minister of Law and Order, and several others was convicted of the murder of Frank Chikane, an anti-apartheid priest, in 1989, and received a suspended prison sentence. In 2016 van der Merwe demanded that the then presidentJacob Zuma, former president Thabo Mbeki, and former senior ANC member Mac Maharaj should be charged for murder.
