(CBS News) WASHINGTON -- The U.S. government unsealed papers Monday detailing the arrest and interrogation of a senior terror leader, a development one official called "an intelligence watershed."
For the past two years, Ahmed Warsame has been cooperating with U.S. interrogators, revealing inside details about training, operatives and potential plots.
Warsame was a key commander for al Shabaab, the al Qaeda-linked terrorist group based in Somalia. Al Shabaab has attracted dozens of American recruits, including Omar Hammami, a propagandist born in Alabama.
Court papers unsealed Monday reveal Warsame pleaded guilty to being an operational link between two terror groups -- al Shabaab in Somalia and al Qaeda in the Arabian Peninsula, based in Yemen.
The 25-year-old Somali wasin the Gulf of Aden as he was traveling from Yemen to Somalia. He was carrying extensive files and handwritten notes about how to build bombs.
It was all part of a terror-exchange program, and Warsame was a broker. He funneled money and communications gear from Somalia to Yemen in exchange for weapons and explosives for his Somali fighters.
After his capture, Warsame was held aboard a U.S. ship and secretly interrogated for two months.
In July 2011, he was flown to New York and appeared before a judge. He continued to talk to interrogators, repeatedly waiving his rights, as he laid out more details about al Qaeda operations.
Officials will only describe the intelligence he provided as "enormously valuable," but he does understand how terrorists move money and people. Most importantly, he knows how the affiliated terror groups are connected and what their joint capabilities might be.
The U.S. brought him into the civilian court system instead of sending him to Guantanamo Bay, because the Obama administration is trying to make a point: Terrorist prisoners can be prosecuted in U.S. civilian courts. But it's also true the government took its time to exploit all of the potential intelligence, questioning him for two months at sea -- outside the criminal justice system.