(CNN) -- On May 16 last year, a 22-year-old Austrian named Maqsood Lodin was being questioned by police in Berlin. He had recently returned from Pakistan via Budapest, Hungary, and then traveled overland to Germany. His interrogators were surprised to find that hidden in his underpants were a digital storage device and memory cards.
Buried inside them was a pornographic video called "Kick Ass" -- and a file marked "Sexy Tanja."
Several weeks later, after laborious efforts to crack a password and software to make the file almost invisible, German investigators discovered encoded inside the actual video a treasure trove of intelligence -- more than 100 al Qaeda documents that included an inside track on some of the terror group's most audacious plots and a road map for future operations.
Future plots include the idea of seizing cruise ships and carrying out attacks in Europe similar to the gun attacks by Pakistani militants that paralyzed the Indian city of Mumbai in November 2008. Ten gunmen killed 164 people in that three-day rampage.
Terrorist training manuals in PDF format in German, English and Arabic were among the documents, too, according to intelligence sources.
U.S. intelligence sources tell CNN that the documents uncovered are "pure gold;" one source says that they are the most important haul of al Qaeda materials in the last year, besides those found when U.S. Navy SEALs raided Osama bin Laden's compound in Abbottabad, Pakistan, a year ago and killed the al Qaeda leader.