After Erdiş 's arrest and subsequent conviction on December 29 , 1998 , followed by the detention of many lower-ranking figures in the group , IBDA-C 's activity seemed to quiet down . However , IBDA-C burst back into the headlines when it claimed responsibility for the dual synagogue bombing in Istanbul on November 15 , 2003 , which killed 24 and injured 255 , as well as a subsequent attack on the HSBC Bank and British consulate on November 20 , 2003 ( see 2003 Istanbul bombings ) . The second claim called the bombings a joint attack with Al Qaeda ; the authenticity of the claim is disputed
2003 Istanbul bombings
2003 Istanbul bombings
Great Eastern Islamic Raiders' Front