I'd have to say this is pretty damn' spot on if the rest of the article is true (and it rings true to me ...)
They are sat down, told to not do anything, say anything or discuss anything UNTIL they get an attorney. At which time, the attorney is handed a letter from the investigating unit. That letter says in essence, this is how screwed you are. If you want to be less screwed you will sign this letter of cooperation and assist us. When we dont need you, you sit there. When we do we will call you and you will provide what we need. Any deviation from this agreement lands you in jail for the full term.