The United States should question terror suspects as soon as humanly possible because sometimes intelligence has a shelf life. Questioning terror suspects in international waters also means international law is in effect so prisoners have certain rights as opposed to following laws of countries within 200 miles offshore. The Geneva Conventions are in place while sailing in international waters, so torture shouldn't come into play.
As long as the questions are done humanely, there is no problem in questioning a suspected terrorist. A country has the right to question those who may threaten it. Questions do not have to be physically aggressive. If care is taken not to torture, harm, or hold indefinitely those who are questioned, it is justified to question people in international waters.