As wrong as the media may/may not be with some of these aspects, I do not blame them one bit for the warrant news. Supposedly a warrant has indeed been issued on paper, but not signed or entered into the database. That may be due to a potential squeeze play which they hoped would enable him to talk more, which is a very common ploy in serious crimes or when more information or cooperation is needed.
In cases where they want someone to talk more (drugs, murder, even burglary and other "cycling" crimes that are somewhat serious in nature that usually don't have the highest conviction rates) they often issue what is called a "paper" warrant as opposed to just issuing one into the state/national database for ANY law enforcement official to act on. The object is to have one or two detectives obtain this "paper" warrant as a bit of a bargaining chip. In other words it is used in many instances as "we have you already, so any cooperation is going to help you tremendously." There is also a kind of "good cop" feel to it in a sense of "I have the power to arrest you right now....but I'll hold off on this if you can help me with some more information." Obviously if they really wanted the warrant to be acted upon, they would simply present it to him and/or enter it into the database. At this point it certainly seems as though they do NOT want anyone else to pick him up, as they feel his cooperation level would be at its lowest point then.
Sometimes the paper warrant turns into an actual arrest, and sometimes it doesn't and is only used as a bargaining chip for more cooperation and information. The fact that it's been reported that it hasn't been signed yet may lead some to believe that they are simply fishing for more information and cooperation from AH, who they obviously believe can help them get pointed in a better direction one way or another, and who currently has a lot of suspicion surrounding him.