Original title Fasandræberne (2008) was released last September under the Spanish title Los chicos que cayeron en la trampa (Maeva, 2011) translated by Nicolás de Miguel. You can check HERE the information from the Spanish publisher (in Spanish). This is the second volume in Department Q series. The rest of the series, to my knowledge, is made up by the first in the series Kvinden i buret/The Woman in the Cage aka Mercy/La mujer que arañaba las paredes, and Flaskepost fra P/Message in a Bottle/El mensaje que llegó en una botella. The last one will be released in Spain by mid-January 2012.
There is additional information about The Pheasant Killers at Jussi Adler-Olsen official webpage HERE (in English) and at the Foreign Rights section of JP/Politikens Forlagshus HERE (in English).
I trust this information may be of your interest.