Whole families have been killed by Zouabri's group
For many years, the name of Antar Zouabri - the head of the Armed Islamic Group (GIA) who has been killed by the Algerian security forces - has been synonymous with the most horrific violence against the country's civilians.
Mr Zouabri came to the helm of the GIA in the summer of 1996, shortly before it started a campaign of slaughter in the countryside.
He was killed along with two colleagues in a house in his hometown of Boufarik, near Algiers.
"Subversive documents" and weapons were found in the house, officials said.
Mysterious figure
Whole families, including children and even babies, had their throats slit in attacks attributed to the GIA.
Throughout, Mr Zouabri and his organisation have remained shrouded in mystery with very little known about their motives or strategy.
Some Islamists outside the GIA say it relies on extremist interpretations of religion which allow it to target civilians it suspects of siding with the authorities.
Mr Zouabri himself has been quoted as saying that whoever was not with the group was renegade.
Massacres
Algerian opposition sources allege that the group may have been manipulated at times by elements within ruling military and intelligence circles.
A series of massacres in the summer of 1997 - in which many hundreds of people were killed - took place near Algerian army barracks, but no-one came to the help of the victims.
The attackers left after hours of slaughter without the slightest attempt to apprehend them.
The GIA is one of two Islamist groups still fighting in Algeria.
It has probably been weakened in recent years after hundreds of members gave themselves up under an amnesty offered by the authorities.
Nonetheless, it is still active in parts of the countryside and there is no certainty that the loss of Mr Zouabri means the end of its activities.
Last week 22 people were killed in western Algeria in attacks blamed on the GIA. They include nine people who were ambushed on a country road, and 13 members of the family of an armed civilian guard.
Significance
It is difficult to gauge the extent of the blow which the killing of Mr Zouabri represents to the GIA.
He was the longest serving of eight leaders which the group has had in its 10-year history. The organisation, believed to be a loose structure of groups operating in different parts of the country, has always managed to replace slain leaders, even when they have been killed in factional infighting.
The other group still active in Algeria is the Salafist Group for Preaching and Combat (GSPC) headed by Hassan Hattab.
It is a splinter from the GIA, and its actions are confined to attacks against military and police targets. It said it broke away from the GIA because it did not agree with its policy of indiscriminate killings of civilians.