This paper is based on the so called 1981 "Yorkshire ripper", which is the British criminal suspected of 13 murders. To crack the serial killing, the triangular distribution and cluster analysis are used to analyze the details of case. Combined with criminal psychology, we can find out the mass center of criminal attack sites and obtain the geographical contours, so as to eventually narrow the searching scope. These two different methods demonstrate that the criminal sites approximately concentrate in two regions, Leeds and Bradford, of which Leeds is the key areas of criminal perpetrators. The place where Peter Sutcliffe was arrested is closed to the location of our model given. It shows that this model is feasibility.