Cecilie, police custody is not the same as arrest. The grounds for detaining a person for questioning are lower than the grounds for arrest. If grounds for detention exist, most jurisdictions can hold you for up to 24 hours without issuing an arrest warrant
If I may my friend, jailhouse detention for questioning on less than probable cause is UNconstitutional, there is no such thing as "investigative detention" in the U.S., see Dunaway v. New York, 1979, USSC.
*Curtseys*
Thankies for the correction, lawbuff.
Thank you for the nice post.