Good point.
But if you arrested them, you could spend some time talking to them, maybe get some leads.
You could tell anyone who is interested that they are being arrested, because they are suspects- they seem to want to talk right?
Maybe you could even get some reporters helping by asking them questions.
Or how about forget about arresting, invite them to exclusion press interviews, then pre-interview these guys. You could then have these demonstrator speak on Iraqi TV (must be a shortage of content, so why not fill it with these guys answering questions and what they think should done, etc). Hell, there probably tons of TV channels with static- fill all the channels with this stuff. They want to be on TV, make them work:)