The Interpol officials, Japanese Hiroshi Sumi and US citizen Marc Beauchemin arrived here Monday as an advanced need assessment team. They were tasked to find out what expertise and logistics are required for proper investigation of the August 21 carnage.

Prior to their departure, the Interpol men met the officials of the CID and other intelligence agencies engaged in the investigation at Sonargaon Hotel. They flew back to Lyon on a Thai Airways aircraft at 12:00noon, police sources said.

They will submit a review report on their visit, based on which another team will arrive shortly.

The next team will probe mainly the August 21 and January 27 carnage on Awami League rallies in Dhaka and Habiganj and grenade attack on the British envoy in Bangladesh, said a CID official asking not to be named.

The team will continue investigation until coming to a successful end, while the government will bear all expenses, the CID (Criminal Investigation Department) official added.