One al-Qaida operative also advises where additional reconnaissance could be performed before an attack, such as ``inside the coffee shop, restaurants or bars etc. Or even on the upstairs floor of the bookshop (there is one end where people regularly sit and browse through books).''
The bulletin said the casing reports demonstrate a high level of sophistication among al-Qaida surveillance operatives and suggest that the terror group wants to use people who have experience living in the United States to help choose targets.
Many of the reconnaissance techniques are described in a captured al-Qaida manual titled ``Military Studies in the Jihad Against the Tyrants.'' That manual says that public information can provide 80 percent of the information needed about a possible target, demonstrating that security officials in government and the private sector must carefully review what is available on the Internet and elsewhere, the bulletin said.
``Surveillance of a potential target can occur as little as one week to as much as three years prior to an attack,'' the bulletin said.