The Pakistani stance

Pakistan has "arrested" another 20 in relation to the Mumbai attacks. (I put that in quotes because, at this point, there are real questions as to what level of serious legal jeopardy these folks will face. Several of them have been repeatedly arrested and released over the years.)

The important bit is that, in these arrests, Pakistan is strongly asserting that it will not turn any of them over to India. (AP, BBC)

Politically, domestically, Pakistan can't turn them over, but would a domestic conviction serve them any better? Or are these guys detained until the political winds blow over?