Officials say that in early 2009 , group set off from Hamburg for tribal areas of Pakistan . Police detained a group member before he left ; 2 others arrested after arriving in Pakistan . Comment: Border area group is linked to plot that prompted advisory for U.S. citizens traveling in Europe .
Officials say that in early 2009 , group set off from Hamburg for tribal areas of Pakistan . Police detained a group member before he left ; 2 others arrested after arriving in Pakistan . Agencies think other members of the group remain in the Afghan/Pakistan border area . Border area group is linked to plot that prompted advisory for U.S. citizens traveling in Europe .