This chapter develops the theory of ethnic vigilantism and evaluated it and other explanations in two ways. First, it analyzes data taken from neo-Nazi publications. The theory of ethnic vigilantism performed well in this evaluation. Second, it provides further evidence for a reciprocal logic to skinhead violence with interview data from skinheads. The chapter provides observable implications of the theory of ethnic vigilantism and competing frames for violence. It evaluates these explanations using a content analysis of neo-Nazi media, demonstrating that the theory of ethnic vigilantism provides the best explanation for the characteristic forms of violence. The chapter presents the data, which analyzes interviews with skinhead perpetrators of violence. It argues that the results concerning Roma must be treated with caution and that the failure of the few stereotypes of Roma present in the data sample. The chapter demonstrates that the theory of ethnic vigilantism passes an important evaluation.