Originally posted by: klah
The AP posted an addendum to this story with the change from "arrested" to "indicted".
Regardless, you can be detained without actually being arrested. Being arrested implies that you have been formally accused of committing a crime, while you could be be detained voluntarily, or for your own protection, but your detention could lead to your arrest.
Of course, based on the constution, you can't be detained without being charged, so you can request to either be charged or released, and quickly.
*IANAL