An interview with David Kirkpatrick of The New Yorker on Fresh Air on Wednesday included a discussion of his interview with one of the political leaders of Hamas. It's worth a listen; the whole thing is interesting but skip to about 25:00 - there is an awkward transition from the ADF discussion the the Hamas discussion (they overlap, no transition), but it gives more information about what they know about that explosion at the hospital and about the political activity of Hamas.