School principal Theuns Botha planned to rape his students, whom he "hand-picked" because they were vulnerable.
Botha, whose prosecution took more than a decade, turned bright red in the Benoni Magistrate's Court yesterday when Magistrate Ian Cox sentenced him to 11 years in jail for the crimes he committed about 20 years ago.
The middle-aged principal of Hoër Volkskool in Heidelberg, southeast of Johannesburg, remained at his desk after his conviction until The Times brought the fact that he had returned to school to the attention of the national Department of Education.
He was suspended two weeks after his conviction.
Throughout his trial, Botha was supported by some members of the Heidelberg community who, despite his conviction, did not believe him capable of the crimes.
But Cox described Botha as a predator.
"This wasn't a random, once-off act. It took a degree of specific planning," Cox said.
"It started with little kisses, then [he] would check the girl's reaction before moving on to other sexual acts."
One victim was in Botha's care, not only at school, but was also living at his house with his family and "trusted him as a father figure".
The court heard how the woman had been so traumatised by Botha that it negatively affected all her relationships with men.
She was quoted as saying: "Everything that went wrong in my life was because of him."
Basic Education ministry spokeswoman Hope Mokgatlhe said the ministry welcomed the sentence.
She said the department was satisfied the law had done everything to ensure his conviction.
She said: "We are worried about the elements of abuse from people in authority who are entrusted with children's safety and well-being.
"We are happy the media and the law have helped uproot such people."
The department suspended Botha, who had returned to his post at the high school following his conviction, after The Times informed it of his return.
Another media report had led to Botha's arrest.
He was first arrested in 1998, on charges of sexually assaulting three girls at the prestigious high school, but was acquitted the following year.
He was suspended by the Department of Education, but was reinstated as principal on his acquittal.
In 2002, he was arrested when two women, one from Potchefstroom and the other from Vanderbijlpark, claimed that he had sexually abused them when they were matric pupils at schools at which he taught before becoming headmaster in Heidelberg, as far back as the 1970s.
The allegations against the principal came to light after a Sunday newspaper called on people who had fallen victim to him to come forward.
Leaving the court after the sentencing, a female friend of Botha's, who spoke on condition of anonymity, said this was all part of a "conspiracy" against him.
"I'm devastated and heartbroken by all this," she said. "He does not deserve this. Someone is out to get him."
Botha was granted leave to appeal the sentence, but remains in custody until the appeal is heard on November 17.