Retrieval of dead game on private property

My friend recently killed a bull elk with his bow. Before dying, the animal entered private property. The land owners will not let him retrieve the dead animal. What are the laws regarding this scenario?
Answer: 
Hunters must make a reasonable effort to retrieve and reduce a wounded animal to possession.  It is unlawful to enter private property that is posted, cultivated or in irrigated pasture without landowner permission to retrieve game.  If permission is requested and denied, the hunter has made a reasonable effort.
Answered on: 
Monday, September 22, 2014 - 8:00 AM MDT