The pupil who killed a Zimbabwean teacher in South Africa after failing a grade has been jailed for just 12 years.

Kingston Vhiya taught in Northern Cape and was stabbed to death by a Grade 9 pupil in his home.

"Not so long ago someone was sentenced to life imprisonment for stealing and being in possession of rhino horns, yet this boy who stabbed and killed a professional teacher in cold blood was sentenced to only 12 years? Our justice system has failed us," said Senzo Mpalala, chair of the teachers union, Sadtu in the province.   

The union said it had been following the case and the pupil had not shown any remorse nor empathy and as a result deserved nothing short of life imprisonment. 

"He deserved nothing short of a life sentence. We had hoped he would receive a harsh sentence that was going to send a loud, unambiguous message that such acts are not allowed," said Mpalala. "The boy doesn't show any remorse, you can't sympathies with someone like that," he said.

A fellow Zimbabwean teacher and friend, Angeline Pahla said she was so shocked to learn of her "homeboy's" brutal death, she had to move out of the Manyeding village near Kuruman.

"I was devastated and scared, I even moved out fearing that I too could be attacked. I now stay very far from the school," she told Times.