Following one of the most violent weeks in Algeria for years, speculation is likely to intensify about the strength of an Islamist group linked to al-Qaeda and the security forces' ability to counter militants that have been using increasingly sophisticated and deadly means of attack.

Although no group has claimed responsibility for either the suicide car bomb attack on a police academy on Tuesday or the two car bombings the following day - that time remotely detonated - the killings bore the hallmarks of a group calling itself al-Qaeda in the Islamic Maghreb (AQIM).