Boeremag bomber Herman van Rooyen became the fifteenth man to be convicted of high treason by the High Court in Pretoria on Wednesday.

Van Rooyen, a farmer in Bela Bela, was the Boeremag's military commander in Limpopo and headed a bombing campaign late in 2002 aimed at causing a racial war in South Africa.

He was part of a group of accused who tried to kill former President Nelson Mandela with a bomb near Bolobedu in Limpopo in October 2009.

The bomb had been planted along the route which they hoped Mandela would travel on his way to open a school. He arrived in a helicopter instead.

Van Rooyen participated in planting bombs at the police's air wing at Grand Central Airport, a bridge in Port Edward, and a railway line in Soweto.

Under his leadership, several bombs were triggered at the same time in Soweto on the night of October 29, 2002. Claudia Mamatsieng Mokone was killed when a piece of steel was flung into her shack by the railway line blast.

According to witnesses, Van Rooyen and his group had been very satisfied about the success of their bombing campaign in Soweto, and laughed when they saw on television that a woman had been killed.

He had also been one of the leaders during the Boeremag's failed D-Day plan in September 2002 where a group of men were on their way to start a bombing campaign aimed at overthrowing the ANC government.

Judge Eben Jordaan said the arrest of some of the Boeremag members had not stopped Van Rooyen, who refined his coup plan and continued it with a small group of fellow accused.

He had undertaken reconnaissance work to identify targets for the bombings, including a taxi rank and a mosque on the Potchefstroom road.

At one stage, he was involved in plans to free fellow Boeremag members from prison and to kill policemen and prosecutors involved in the investigation against the Boeremag.

Plans to kill investigating officer in the Boeremag case, Superintendent Tollie Vreugdenburg, were apparently canned because he was popular, had solved many farm murders, and "had a very pretty daughter".

Van Rooyen had given instructions for the large-scale manufacture of fertiliser, shrapnel, and car bombs, which he said "would have the same effect as the Bali bomb" (in Indonesia in 2002).

According to the evidence, he was unconcerned that people could be killed, saying it was a time of war and people would most certainly die. He told witnesses his group of whites were God's chosen nation and said they wanted to chase blacks out of the country.

He had also shown a witness a sketch of his plan for a revolution.

He said bombings in Soweto would cause blacks to start attacking whites, and to turn against the ANC government, because they would not be able to catch the bombers.

He and State witness Deon Crous were on their way to Pretoria with a large car bomb destined for Marabastad when they were arrested in 2002.

Van Rooyen and fellow accused Rudi Gouws were on the run for months after managing to escape from court cells in 2006. They were part of a group that staged a failed escape attempt at the court last year.