For this post, I'm using the terminology "captive" of someone that is arrested by the police for something for the lack of a better word off my head.
http://politiken.dk/indland/ECE2461...mark-politiet-er-oftere-good-cop-end-bad-cop/
This article (Danish, sorry) talks about some differences between Danish and American police.
I know "American" is a broad, most probably imprecise stroke, but I still feel I should mention some things.
According to the article, American police uses a so-called "Reid" method which is intended to break down a captive and can lead to false testimony and a false confession. The method accordingly has the intention to break those down the police is already targeting, not the intention to have the captive provide an as-good-as-possible testimony. In Denmark the intention of interrogation is to have the captive provide information, not to frame the captive. The article directly talks about an anecdote of a Danish pedagogue who broke down during an American interrogation and was falsely accused and jailed for nine months.
Additionally, the article states that apparently cops are allowed to lie to captives in America. They are not in Denmark. They're allowed to withhold information, but not to lie. On the other hand, withheld information may not be evidence, the captive must be informed about evidence so it can figure out what to do with it with his or her lawyer.
Of course, sometimes Danish police officers don't follow the rules and can make informal hearings, for example, gathering information during casual chatter, or when the defending attourney isn't present. But testimonies provided during this period is not legitimate information for court and as such the judge will not allow information provided during informal hearings.
Even with this state of things (If it is truly a difference between Danish and American legal systems, I sincerely hope your state's police department isn't like what is informed in this article) this article is actually going into criticism of Danish police when it hasn't acted according to the law. It mentions an episode when some Danish officers have taken a captive out for coffee and interrogated him informally (it's very normal to temporarily incarcerate suspects in Denmark so some time outside is very welcome to a captive. That said, our prisons are really, really humane, prison cells look like small apartments) which the lawyer said was illegitimate evidence. Additionally, the difference between the written and spoken (court) testimony is sometimes too large and when the difference is there, it’s usually making the suspect’s case worse.
Still, I think this is just about the actual extent of current police corruption in Denmark.