As three pit bull terriers, owned by a police officer, mauled a seven-year-old boy to death, his grandfather tried in vain to fight them off, police said on Monday.
The boy's grandfather was also taken to hospital, but was lucky to escape with his life, said spokesperson Captain Cherelle Ehlers.
Police are baffled as to why the dogs pounced on young Austin Pieters, and how they had managed to get out of their yard in the small town of Kenhardt, in the Northern Cape.
"The dogs got out of their yard and walked 3km by the time they came across the boy," Ehlers said.
"He was playing with his grandfather on a sand dune."
The boy died in hospital on Sunday.
Ehlers said the police officer, an inspector, had been with the police for many years and arrived at the scene soon after the attack.
She described the attack as a "vicious" one, and said the boy had suffered multiple injuries.
"Just imagine three pit bulls and a tiny boy," she said.
The National Society for the Prevention of Cruelty to Animals (NSPCA) said it was a horrific incident.
"It keeps happening. And we have to ask why?" said spokesperson Chris Kuch.
She referred to similar cases in Pretoria, where a man over 80 was mauled to death, and in the Western Cape, where a dog owner was convicted of manslaughter when his dogs killed a person.
"When's it going to end?" Kuch asked.
Ehlers said the dogs had been confiscated from the policeman and were being kept at the Upington Dog Unit.
A senior state prosecutor would decide whether the dogs would be put down.
"It's out of control," Kuch said.
"The owners are responsible and should make sure their dogs are not out of the property.
"This is an absolute tragedy."