Sri Lanka launched an investigation on Tuesday into its deadliest prison riot in years, as the death toll from clashes between rival drug gangs rose to 27. Armed police and commandos were not sent into the prison but were deployed to guard the perimeter of Negombo prison, as authorities tightened security following the clashes on Monday that also wounded more than 100. Justice Minister Harshana Nanayakkara told parliament on Tuesday that a criminal investigation had begun alongside a...