(CBS News) A new document filed in a still-developing terrorism case in New York seems to confirm the long-held fear that al Qaeda is working to develop chemical weapons.
On Wednesday, CBS News obtained a document filed by the United States Attorney's Office for the Eastern District of New York indicating that three men charged with being members of the al-Shabab terrorist group in Somalia had "substantial knowledge regarding an al-Shabaab research and development department that was developing chemical weapons."
CBS News senior correspondent John Miller told "CBS This Morning" the lead defendant in the case, Mahdi Hashi, and two others were arrested in August, 2012, by African authorities while allegedly on their way to Yemen. They are charged with participating in a weapons and training program with al-Shabab over a four-year period beginning in 2008.
Hashi, who left his home in the U.K. to join the Somali group, had been part of an elite suicide bomber unit with al-Shabab.Below: "CBS Evening News" report on threat posed by AQAP
The new document says the defendants' planned to join, or AQAP, the terror network's branch in Yemen which has orchestrated numerous recent, high-profile a terrorist attacks, including plots targeting the U.S. mainland.
Miller, who is a former assistant director at the FBI, notes that developing chemical weapons is a goal al Qaeda, "seems to be striving for."
But Miller notes that neither the new court document, nor, to his knowledge, current U.S. intelligence, reveal a clear timeline regarding when al Qaeda might actually be able to produce a finished chemical weapons agent or gain the capacity to use such a weapon against the United States.
Miller adds, however, that the mere "idea that they have a department and that they have capable, knowledgeable people in that department who are striving towards it is ... very concerning" to U.S. intelligence organizations.
Miller said that in the context of what's going on now in Syria -- where al Qaeda-linked or inspired militants are thought to comprise anywhere from 15 to 50 percent of the rebel fighting force on the ground -- the threat of al Qaeda's chemical weapons ambitions is two-fold: that they might be developing their own weapons, and that they could gain access to military-grade weapons developed by governments in Syria and the Middle East.
A former top CIA analyst told CBS News a week ago that if Syria's government fell, the al Qaeda elements in the country could gain access to the estimated 1,000-ton chemical weapons stockpile currently under President Bashar Assad's control.
In June, authorities in Iraq -- from which many of the jihadi fighters in Syria came -- arrested five alleged al Qaeda militants and raided three alleged chemical weapons manufacturing laboratories across the country. The government claimed the men were trying to make sarin and mustard gas to use in attacks in Europe and North America.
The only al Qaeda affiliate known to have manufactured and used chemical weapons to date is al Qaeda in Iraq, which waged attacks in 2006 and 2007 using bombs containing chlorine, which failed to kill anyone.
Outside of trying to acquire existing chemical weapons, "al Qaeda is more than likely trying to develop their own homemade sarin or working with readily available commercial-industrial products that can be turned into dispersal devices that can be deadly," said Miller.