I can understand why they may not want to "out" him unless and until they are fairly certain he's the guy, as they don't want a lynch mob or another Richard Jewell situation.
I think that's the key here. Question is, which media reported it, and who has the picture? The media? Then what makes them so certain it's the right guy? Or the investigators? They may not want to release the picture until they're dead certain. This is something where mistakes can be fatal.