One of the arguments that DF did out forward for putting up new border checks in Denmark is to stop the crime wave that has been taking place in Denmark after an eastern Europe countries joined the EU and later Schengen agreement.
This crime waver is an myth in Denmark as it is in the United Kingdom (not in Schengen by the way). But an study conducted in the year 2008 by the UK police. What happens to be an myth in one place also happens to be an myth in other places too. So it an save bet that DF claims are nothing but an hogwash and lies. Something that the danish media should have spotted an long time ago.
This discussions and claims have also been going on in Iceland for the past months. The same myths have been claimed, along with the same lies. But the interesting fact here in Iceland is that even with many foreign criminals in icelandic jails, they only make up 22% of the total prison population. The rest, the 78% are Icelandic criminals. That number had risen from 8% since the year 2001. But that has nothing to do with Schengen, but the fact that in the year 2004 and 2007 many countries did join EU and many more people where added to the area that allowed free people movement inside Europe. Sadly, I do not know the statics for Denmark jails in this regards, my danish is not that good yet.
This has nothing to do with Schengen, but it is popular by the populist extremist in the politics to cast the blame in Schengen agreement. As it is easy to blame, and nobody seems to check there claims to see if they are actually true of not. That is why the DF gets away with telling lies in the Danish media as it has done so for an long time now.