According to my social structure crime theory, crime happens because of your surroundings and social history. I believe that where you come from and the experiences that you have can and will effect the choices you make later in life. As stated in this crime report, the son of a former police officer admits to murdering his ex-girlfriend. His reason for commit this crime was that it was in self-defence, and he believed that his ex-girlfriend was in a group of serial killers planning on killing him. This reason appears to show some traits of mental illness or disillusionment. But I believe is more to it than just a mental state.
The prosecuted is the son of a man who upheld the law everyday as a profession. His life was driven and ruled by laws and regulations and that was possibly all that he taught his son at home. Everyday the young man was probably told story after story of crimes that his father worked on. This young man was no amateur to knowledge on criminal ideas and how the criminal mind works. In my opinion his growing up was constantly bombarded by crimes from outside of his home brought in by his father who worked with them all day. It is impossible to completely separate the home and the workplace.
There is also no way to tell if the household environment was exceptional. There could have been divorce and abuse and death that also may have effected the young man negatively to the point of murder. After all that happened in his family and then breaking up with his girlfriend who he may have been with for a long time possibly caused enough stress and anger to make him commit a crime as serious as murder.