21.   It is rare that the GIA claims individual attacks.

22.   It usually claims its attacks several weeks later.

23.   Leaflets claimed the attacks in the name of the Islamic militant group Hamas.

24.   Most attacks have been claimed by shadowy groups little-known to authorities.

25.   Most previous attacks have been claimed by Islamic militants or radical groups based in Damascus, Syria.

26.   No one claimed the attacks.

27.   Neither attacks were claimed by Saturday night.

28.   No credible organization has claimed the attack, but names mentioned have included Saudi-born fugitive Osama bin Laden.

29.   Police headquarters said that a previously unheard of group calling itself National Struggle claimed the attack.