These underworld figures include 'Kosgoda Tharaka', 'Podi Lassi' and several others who were transferred to Boossa Prison.
It is said that a team from the CID including ASP Meryl Ranjan Lamahewa had visited the prison headquarters yesterday (20) and obtained statements from high ranking officials.
Meanwhile, several underworld leaders including 'Kosgoda Tharaka', 'Hikkaduwe Podi Lassi' and 'Pitigala Kavuma' had started a hunger strike to protest against them being sent to Boossa Prison.
Prison officials had gone to the Boossa prison on June 26 to investigate.
There, the group had become violent, threatening the prisons with death and stating that neither the President, the Defence Secretary and other officials were too big for them. They had stated their network with arms and members were active.
The prison officials had complained on this regard to Commissioner General of Prisons Thushara Upuldeniya and accordingly, the CID had commenced investigations yesterday (21).