I have no information beyond what's contained in these links: here, here, and here. Many readers will recall the scandal of Norman Finkelstein's politically motivated firing several years ago, in which the DePaul Administration behaved disgracefully. More recently, the same Administration, with its characteristic heavy-handedness and lack of academic judgment, axed the Dean of the law school and appointed a replacement without even consulting the faculty. That history certainly should make one skeptical that they have behaved honorably in this instance.
UPDATE: Some of these links imply that the decision to deny tenure was made initially at the departmental level, which would complicate the picture considerably. But, again, it's not entirely clear what the process was based on these initial reports.