Chadian soldiers examine Weapons left behind by Boko Haram in Malam Fatori

Security forces in Chad have arrested 60 suspected Boko Haram militants and dismantled a cell responsible for two suicide bomb attacks in its capital on June 15, the chief prosecutor of the central African nation said on Sunday.

Blasts in two police offices in N’Djamena that appeared to have been coordinated killed 34 people including four suspected Boko Haram militants and injured dozens. It was the largest attack of its kind in Chad.

“An active cell of a terrorist network has been identified and dismantled,” said prosecutor Alghassim Khamis, adding that those arrested came from Chad, Cameroon, Mali and Nigeria.

He identified one attacker as Issa Oumar, alias Issa Tchoulou, but did not give his nationality. Bomb fragments collected at the sites had been turned over for analysis to the U.S. Federal Bureau of Investigation, he said.

Communications equipment has been seized and thanks to new technology, witness testimony and an examination of the victims it was clear the attack was well planned with explosive vests made from a specially-constructed black tissue, said Khamis.

Chad has played a leading role in helping Nigerian forces win back territory from Boko Haram, which has mounted a six-year insurgency to carve out an Islamist caliphate in Nigeria’s northeast and attacked neighbours Niger and Cameroon.

The Chadian capital is a command centre for a regional force in the fight.