The hostage-takers phoned in regularly with up-to-the-minute reports, offered eerily accurate numbers of hostages taken and killed, and clearly laid out their goals.
All this came via a Mauritanian news website that apart from receiving calls from radical Islamists and al-Qaida-linked militants is known for its reliability on more mundane local news.
Algeria's official information, in contrast, was silent and murky. At one point the state news service even went dark online before returning with a home page scrubbed of all mention of the hostage crisis that had riveted the world.
When Algerian officials were willing to comment only anonymously their information drastically underplayed the scope of the hostage siege that left at least 37 captives and 29 militants dead and sent scores of foreign energy workers fleeing across the desert for their lives.
The reliability of the information from the kidnappers was a departure from the more bombastic and exaggerated announcements typical of al-Qaida-affiliated insurgents in Iraq, Afghanistan and other conflicts.
Also, instead of publishing statements on a password-protected jihadi website entirely in Arabic, the Masked Brigade that claimed responsibility for the gas plant attack sent its information to a news website published in both French and Arabic, reaching a much wider audience.
"It was in the interests of the gunmen to get their story out and the Algerians didn't perceive it was in their interest to get the story out in real time," said William Lawrence, the North Africa analyst for the International Crisis Group. "The gunmen needed to negotiate through the media, politicize the Mali conflict through the media, and score jihadist points in the media."
The editor of the Mauritanian site, the Nouakchott Information Agency, also known as ANI, attributed the difference in style to the Masked Brigade's founder, Moktar Belmoktar.
"Moktar is a man who speaks frankly of what he wants, he's straight forward," said El Mokhtar Ould Sidi, who added that his site left out the parts of the kidnappers' statements that he deemed to be propaganda. "It's very different from al-Qaida in the Islamic Maghreb or al-Qaida central."
Figuring out what was happening during North Africa's most audacious terror attack was no easy matter with the Ain Amenas natural gas complex deep in the Sahara desert, more than 800 miles (1,300 kilometers) from the capital, Algiers.
Despite a vibrant local newspaper scene, Algeria is not an easy place for foreign journalists to operate and information about security matters is kept under tight control by the military-dominated government.
Instead, as the four-day standoff unfolded, it was the regular dispatches from the militants carried by the Nouakchott agency that provided the most consistent source of information.The reports also bolstered the militants' assertions that the Algerian forces had endangered the hostages with their tactics.
No matter how shocking the news was, it seemed to come first and most reliably from the militants.
Soon after the attack began Jan.16, the militants claimed to have seized 41 hostages. That night, Algerian Interior Minister Dahu Kabila maintained there were only 20 hostages and they were being held by a local terror group.
The militants replied by listing their diverse nationalities, including the presence of Canadians something only confirmed by the government several days later.
The biggest revelations came on the second day of the standoff when frantic messages from the militants described Algerian helicopters shooting at the complex's living quarters, followed by a full-scale attack on a convoy of vehicles carrying hostages.
Algerian Foreign Minister Mourad Medelci at the time denied there had been any such airstrike, and all that was reported that day was that the army had foiled an escape attempt.
The ANI, meanwhile, said 35 hostages and 11 fighters were killed, with only seven hostages left alive a death toll it took Algerian authorities several days to match. In the end, their final numbers were quite close.
The accounts of two hostages who barely escaped the doomed convoy, Irish electrician Stephen McFaul and Filipino civil engineer Ruben Andrada, ended up corroborating the militants' version of events.
While the Algerian government claimed the kidnappers were trying to escape with their hostages, the militants were trying to take the captives from the complex's living quarters to the more defensible gas works on the other side when the helicopters attacked.
Being the chosen media outlet for high-profile hostage-takers has not been easy on ANI. At one point, its director was summoned by Mauritanian authorities to defend charges that it was a propaganda outlet for terrorists.
The site was also hacked twice with bogus articles posted blaming the Algerian military for planning the attack and was also savaged in the Algerian press.
Of course, there were important elements of the hostages' accounts that didn't make it into ANI's reports. Algerians evacuated from the site described how the militants searched for foreign workers room by room, killing some outright and booby-trapping others with explosives.
Still, late Thursday after the strafing by its helicopters, the Algerian government claimed its special forces had taken control of the gas plant and insisted that only four hostages were dead.
The next morning it turned out that the standoff was still ongoing. Gradually over the next few days, the official toll rose to meet the one first set out by the militants.
In the absence of official information, including at one point Friday when the Algerian Press Service website shut down for 45 minutes and returned with no stories whatsoever on the standoff, quotes from anonymous officials proliferated. Even material carried by that official news service was often sourced to anonymous officials as the military and police kept up a veil of secrecy.
The local press was filled with assertions from anonymous officials, some of which were wildly untrue.
At one point, an anonymous official confirmed Sunday that 25 burnt bodies had been discovered. That meant, when added to the official toll, more than 80 people were dead in the attack.Yet the final amount the next day was just 66 and it was not clear where the extra bodies had disappeared to.
One area in which there was a zone of silence was the question of any possible Algerian army casualties in the chaotic, four-day fight against an enemy armed with heavy machine guns, missiles and mortars.
It wasn't until Wednesday, four days after the fighting had ended, that Algeria's Ministry of Defense issued a curt statement saying that "contrary to insinuations" regarding casualties, only eight soldiers had minor wounds.
"Algeria has nothing to hide and we opted for total transparency in communicating all information on this matter as soon as it was available," a member of the prime minister's office told the AP on Tuesday.
He insisted, however, on speaking on condition of anonymity, because he said he wasn't authorized to talk to the press.