There was enough to hold him, but if there is enough question and you dont belive the guy is a flight risk and you do not belive he is an imideate threat to the community, you should not hold a suspect.
You can't hold someone indefinitely without charge
Note: I realize that the above common sense basic statement of black letter law is riddled with exceptions in the post-9/11 era but as a general principle it is still mostly true in most cases.