By Adam Levine, with reporting from Barbara Starr, Jamie Crawford and Santiago Melli-Huber
Key al Qaeda online forums have fallen silent in the past two weeks, leaving terrorism experts to wonder the cause and whether a key communications mode of the terror group and its affiliates has been purposely undermined.
The sites, where al Qaeda posts messages and jihadists and wannabe jihadists post messages and discussions regarding their ideology and loyalty, started disappearing on March 23, said Aaron Y. Zelin, a researcher in the Department of Politics at Brandeis University. Zelin also maintains the website Jihadology.net.
The outages were first reported by the Washington Post. No entity has claimed responsibility and U.S. officials contacted by CNN would not comment.
The online al Qaeda ecosystem starts with the different branches of al Qaeda - like al Qaeda central in Pakistan, al Qaeda in the Arabian Peninsula based in Yemen or al Qaeda in Iraq - which produce messages through their own media production wings that are distributed by an entity known as al-Fajr Media, which then redistributes them to the various forums, Zelin explained.
"It is an authentication process" so the forums know the al Qaeda communications are legitimate since they come from the same media group, Zelin said.
But the messages have grown silent, with the last communication from any of the core al Qaeda groups being a message from al Qaeda in the Arabian Peninsula on March 23, the same day the first sites went dark.
Zelin said five key sites, including Ansar al-Mujahidin Arabic Forum and Shamukh al-Islam, both stopped operating on March 23. Another, al-Fida', stopped working on March 25, and two others followed on March 28 and March 30, according to Zelin.
Two, al-Mujahidin Arabic Forum and Shamukh al-Islam, are back and operating, Zelin said, and as a result there has been an increase in traffic because they are "filling the vacuum." Posts on the sites have asked about the problems and the moderator, Abu Sa'd al-'Amili, has tried to to address some of the concerns by posting two essays about the outages.
Interestingly, Zelin noted, al Qaeda in Somalia continues to broadcast new messages, but even though it has pledged affinity to al Qaeda, it does not use the same system for distributing messages.
Zelin speculated the outage could be tied to the recent arrest of Mudhar Hussein Almalki in Spain. Almalki maintained the Ansar al-Mujahidin Forum, according to a Spanish police document provided to CNN. The police document alleges Almalki ran the site and oversaw who could access it, spread information to jihadists and maintained private chat rooms to "carry out meetings with others to give out instructions," according to a translation of the document.
A U.S. official said the United States has been aware of the al Qaeda websites being down and finds it "of interest to us."
Spanish police allege Almalki was a "prominent member" of al Qaeda's propaganda arm, "following the guidelines and instructions of the terrorist organization."
The disruption of the sites is a "big deal," said Will McCants, a former State Department counterterrorism official and currently a fellow at the Homeland Security Policy Institute at George Washington University. One site, Shamukh al-Islam, is a flagship for al Qaeda supporters and one of the first places the terror group's propaganda is distributed, McCants said. Its stoppage is "very crippling."
McCants said it is hard to say why the sites are not working and whether they will come back. Some al Qaeda supporters on the sites still operating are speculating they were taken down, but "unless you are the guy at the top of the food chain," it is really impossible to know. McCants said if the site administrators had taken the sites down themselves they probably would have explained that to their followers, as has been the case in the past.
McCants said it will take time for other message conduits to emerge.
The widespread outages "sound very much like a covert activity to me," said CNN National Security Analyst Fran Townsend. Townsend was Homeland Security Adviser to President George W. Bush. Townsend said even if the United States was not responsible, there are other governments who could have disabled the sites.
In 2010, the British government was believed to be behind a temporary shutdown of the online publisher of Inspire, the Yemeni al Qaeda's English language magazine.
"When you have several go out it sounds like a denial of service attack," Townsend said. "It is not an accident they all go out."
Townsend said there is a perennial debate in the counterterrorism wings of the government over when to allow forums like these to continue operating in order to monitor the messages and when to try to stop them from operating. The decision, if there was one in this case, would be a "very deliberate" one, Townsend noted, perhaps to throw off terror planning.
The hope in interrupting the forums would be to make jihadists communicate in a way that can be better tracked, Townsend explained, like couriers or phones.
The goal for a government would be to push them to communications "where you think they have a better chance" of monitoring, Townsend said.
The move carries risks if you cannot figure out where the communications have shifted to, Townsend noted.
The online forums can be a valuable source for al Qaeda recruitment and fundraising.
"It is a first screen for them," Townsend explained, noting that there have been cases of codes and signals being posted.