Durban – Three teenagers who died after eating vetkoek in Langa, Cape Town added "substances" to their meal, a Cape Town city official said on Thursday. "[Police] have indicated that it does not appear to be food poisoning and that it appears that the children mixed other substances into their food," safety and security mayoral committee member JP Smith said. According to Smith, the environmental health department had been in contact with police in Langa to determine whether they need to conduct food poisoning investigation. "The autopsies will determine [the] cause of death."Police spokesperson Sergeant Noloyiso Rwexana could not confirm if the youngsters added substances to their food.The teenagers, aged between 16 and 17, died on Sunday in Joe Slovo in Langa. A fourth victim was still in hospital, Rwexana said.An inquest was opened for the three who died and an attempted murder case was being investigated for the surviving boy.