A list with two objects. score is a data.frame of the similarity
scores for each element in solved. groups is the data.frame
seriesData with an additional column indicating the crime group
(using the method specified in group.method).
References
Porter, M. D. (2014). A Statistical Approach to Crime Linkage.
arXiv preprint arXiv:1410.2285..
http://arxiv.org/abs/1410.2285