LONDON // The Algerian hostage situation reached a bloody conclusion Saturday with a "final assault" that ended a four-day ordeal.
Now come the questions.
How could such a vital national energy infrastructure installation have been taken so easily and with no warning from intelligence services in a country only recently steeped in a civil war and always vigilant against rebels, extremists and foreign interlopers?
What does that say about the broader security situation in the Sahel and North Africa?
Could Algeria have handled the crisis better?
What is known is that that the raid came less than a week after France sent special forces to Mali to support the military government there against Islamist insurgents in the north.
The French intervention received unanimous support from the United Nations Security Council and was welcomed by Algeria, which opened its skies to the French military. Militants cited the foreign intervention as the trigger for its raid on the gas plant, Ain Amenas.
Also known, 11 militants and seven hostages were killed yesterday. In all, at least 20 hostages and close to 30 militants died. It is not clear if any of the hostage takers survived or how many hostages were wounded or injured.
The motives of the man allegedly behind the raid, Mohktar Belmokhtar, a Mali-based Algerian jihadist, are murky. A former commander of Al Qaeda in the Islamic Maghreb (AQIM), he reportedly left the group because he didn't want to walk away from his own lucrative smuggling operation.
Signatories in Blood, the militant group behind the raid, is reportedly under Belmokhtar's command, and the attack was said to have been planned for months.
The raid began on Wednesday when heavily armed gunmen - some reports suggest they were dressed as Algerian soldiers - attacked two buses carrying field workers heading for the In Amenas airfield.
Two were killed in that initial attack, a Briton and an Algerian.
The militants then commandeered the buses and headed for main residential area of the gas plant, securing as many hostages as possible before taking over the sprawling complex.
Hostage accounts suggest the militants had a close knowledge of the layout of the plant.
The Algerian government says it tried to negotiate, and but was led to believe that the hostage takers were going to move the hostages. That forced the government's hand, officials said, and the Algerian army was dispatched to the complex, about 1,300km south-east of the capital Algiers.
Analysts, however, suggest Algeria was always likely to act quickly and decisively given the country's bloody recent past.
By Thursday morning, the army had surrounded the complex. Some reports suggest that dozens of hostages were killed in the initial bombardment as militants tried to escape the complex with their captives.
But while it seems clear that at least some hostages were killed in that initial raid, Algerian officials have dismissed as "fantasy" militant claims that 34 hostages were killed in that first assault. The government instead said 18 of more than 30 hostage takers had been killed.
Freed hostages, mostly Algerians, meanwhile told reporters that during the initial assault, the militants had separated foreigners from the nationals.
"They came into the bedrooms, they broke down the doors," one freed Algerian told France Info, a French radio station. "They were shouting: We're only looking for the expatriates, the Algerians can leave!"
Some foreigners became human shields. One Northern Irish man who managed to escape during that first assault told family members that he had done so with explosives strapped around his neck.
By the end of Thursday, Algeria felt confident enough to proclaim that its military operation was over. Friday, though, saw little movement apart from reports emerging of a proposed hostage swap. A Mauritanian news agency cited sources close to Mr Belmokhtar said he suggested the release of two Islamists held in the US under terrorism charges in exchange for two American hostages.
The end was, predictably, bloody. After surrounding the last militant holdout, Algerian special forces made their a last assault yesterday around noon.