Ten pupils have been suspended at the Lukhanyo Secondary School, near Randfontein, pending investigations into the alleged satanic murder of a 17-year-old girl, SABC reported on Wednesday.
The 10 were suspended after the death of Keamogetswe Sefularo, who was stabbed on Friday at Mohlakeng.
"It is alleged that the 15-year-old suspect assaulted the victim while on their way from school. The victim died due to her injuries and the suspect was arrested the same evening," Captain Appel Ernst said on Tuesday.
She appeared in the Randfontein Magistrate's Court on Tuesday, when the case was postponed to 12 March.
Ernst said the matter was postponed for the accused to be consulted by a social worker and for a report to be produced.
"The suspect is still in custody and no bail was granted," she said.
She would remain in a juvenile facility.
The Times newspaper reported that one of Sefularo's friends said her killers drank blood from her limp body after stabbing her three times.
The 15-year-old girl reportedly stormed into Sefularo's home on Saturday, while the family was holding a prayer meeting.
"We recorded everything. She told us about how they were instructed by their leader to kill Keamo," Sefularo's brother Zali Nxabi told the newspaper.
" She [the friend] said the leader and the girl who did the stabbing sucked Keamo's blood from [a wound] on her neck."
Nxabi told the newspaper that he had heard rumours of satanic activities in the area, but had never thought they would affect his family.
"Her friend even told us that she [Keamogetswe] knew nothing about the cult and that their leader had always been after Keamo's blood."