My naive and inexpert guess is that Siddiqui may be in custody because
she’s “dishing” on some terrorists/Al-Queda and needs the protection
of the USA for herself and her children.
(VOA’s speculation is based on this passage from this passage from
the Wikipedia article linked in post #1)
Her ex-husband, anæsthesiologist Mohammed Amjad Khan, is now working
as a physician at a hospital in Karachi, Pakistan. Khan and Siddiqui are
divorced following vehement disagreements over how their three children
should be educated. Siddiqui wanted the children to be educated in
the West and to live in America. Khan wanted the children to be
educated in Pakistan under strict Muslim supervision.
Khan’s family lives in a wealthy compound in Karachi.
You might be on to something. But why “acknowledge” she is still alive? If she were working for us now, they would want it assumed that she died, even staging a fake death if necessary. Unless they are either trying to flush al Queda associates out into the open or trying to pressure her into giving up more. Doesn’t make too much sense.