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.