London (CNN) -- A court in London has heard detailed information about the alleged terrorist activities of Anwar al-Awlaki, a Muslim cleric associated with al Qaeda in the Arabian Peninsula, a Yemen-based off-shoot of the group founded by Osama bin Laden.
The details emerged Tuesday during the opening day of the trial of Rajib Karim, a British citizen of Bangladeshi descent accused of helping prepare terrorist acts.
The court heard that al-Awlaki and Karim had been corresponding, via heavily encrypted software, in late 2009 and early 2010. In one message purported to be from al-Awlaki, the writer made clear where his priorities lay: "Our highest priority is the United States. Anything there, even on a smaller scale compared to what we may do in the United Kingdom, would be our choice."
Upon learning that Karim worked for British Airways, al-Awlaki asked for what the prosecution suggests was key terror-planning information; as well as offering Karim clear operational guidance:
"I immediately wanted to contact you to tell you that my advice to you is to remain in your current position," al-Awlaki wrote. "Depending on what your role is and the amount of information you can get your hands on, you might be able to provide us with critical and urgent information and you may be able to play a crucial role."
According to the prosecution, the cleric continued, "I pray that Allah may grant us a breakthrough through you."
Al-Awlaki then sought information on Karim's precise role at British Airways, and the extent of his access to information and the company's IT infrastructure. He also sought details on "limitations and cracks" in present airport security systems.
A few days later, according to the prosecution, Karim sent al-Awlaki a detailed reply in which he suggested his knowledge of key British Airways hardware locations could be useful. If those locations were targeted, he told al-Awlaki, flights could be disrupted causing British Airways financial loss. He also identified three "brothers" in the UK who could be helpful, one of whom worked in baggage handling at Heathrow and another at airport security. "They respect you a lot," he told al-Awlaki.
In another communication, on February 12, 2010, al-Awlaki made it clear that Karim should remain in the UK; he told Karim he should train as British Airways cabin crew if possible. Their plans may take time, he said, according to the prosecution.
"The question is, with the people you have is it possible to get a package or a person with a package on board a flight heading to the US?" the communication said.
Al-Awlaki then asked, "Did any of the [brothers] you mentioned get training on x-ray machines or understand their limitations?" The cleric, according to the prosecution, added, "Is it possible to make false reports on security risks on airplanes and airports? Reports that would cause planes to be grounded and airports closed ... this doesn't count for much but it does cause them some nuisance and loss."
Three days later Karim replied, describing various ways British Airways computer systems could be targeted, as well as informing al-Awlaki that he had applied for cabin crew training, which he hoped he would be accepted for, despite having worked for British Airways for less than the mandatory five years required for such training.
Ten days later Karim was arrested in Newcastle by officers from Scotland Yard's Counterterrorism Command.