Richards Bay - KwaZulu-Natal police are still searching for the fourth pupil allegedly involved in school violence that was captured on video at the Richards Bay Secondary School, on the north coast of KZN.Police spokesperson Lieutenant-Colonel Thulani Zwane on Tuesday said they were still looking for the fourth suspect following the arrest of three pupils involved in the fight on Friday, August 18.The three arrested pupils - all aged 19 - arrested on Monday, are due to appear at the Empangeni Magistrate's Court later on Tuesday for a charge of assault with intent to do grievous bodily harm.In two videos recorded at the school on Friday, a group of boys are seen attacking each other with pangas and knives.Zwane said during their search on Monday they found small quantities of dagga from some pupils."No-one was arrested for that though," he said.READ: Three arrested for Richards Bay School violenceDangerous weaponsKZN Education MEC Mthandeni Dlungwana who visited the school on Monday told the pupils that his department will deal harshly with those implicated in the video."We will harshly deal with those found to be implicated of wrongdoing in these premises," he said.Dlungwana said if there was a need for the department to expel those pupils involved in the fight, "We will do that."We are going to crush all those who think they will take charge of the school as gangs. We will make sure that the learners who know what they want and behave better are protected," he said.On Thursday, August 17, prior to the day of the violence, some pupils carried guns and "very dangerous weapons", Dlungwana said he had heard."We are informed that on Thursday some of you were carrying guns and very dangerous weapons. We are not going to allow gangsters to run our schools," he said.The department would also deal harshly with drug peddlers and users at the school."We are also aware that some learners here are doing drugs. For those who are selling and those who are buying, we are going to be very harsh," he said.