PML-N chief Nawaz Sharif has said that wounds of May 12 massacre in Karachi were still unhealed despite the passage pf four years. “These wounds will remain unhealed unless those who spread terror and established rule of monstrosity are exposed and brought to justice,” Nawaz said in a statement issued on Thursday. He said Karachi would have been saved from the “hell of targeted killings” if an independent investigation had been carried out into the May 12 incidents.