Gauteng Education MEC, Panyaza Lesufi, on Wednesday said there were three pupils from other schools seen on camera footage from the scene after a Mondeor High School pupil was stabbed.
The 19-year-old Grade 9 learner Khulani Mathebula was stabbed to death on his way to school.
Lesufi did not want to speculate as to whether the pupils were involved in the murder.
He said the education department was under pressure and needed assistance from other government agencies to assist with the safety of learners.
Lesufi referred to the situation of being "out of control".
Police said they hoped to make an arrested within 72 hours.
Mathebula's body was only removed several hours after the incident as pathologists and police were gathering evidence.
