Johannesburg - An alleged robber has been killed and three of his accomplices are in hospital after being held hostage and assaulted by an angry mob in Protea Glen, Soweto, on Wednesday morning, Gauteng police said. "Police were called in to a hostage situation where a large group of community members had kept four men who were being accused of being criminals," spokesperson Lieutenant Colonel Lungelo Dlamini said. "The victims were being assaulted. When police confronted the group and rescued the victims, one was certified dead on the scene."A murder and attempted murder docket has been opened but no arrests have yet been made. The other three hostages were taken to a nearby hospital after sustaining serious injuries. A task team investigating the matter would identify those involved in the crime, Dlamini said."Communities are warned not to take the law into their hands. Criminal activities should always be reported to the police."