The rise of right-wing extremism crime and the use of manifestos has become more and more prevalent in recent years. Previous research has established the difficulty of identifying the factors which radicalise individuals and how the process of justifying violent and immoral behaviour can vary greatly. The following study was conducted to study to which extent Gresham Sykes’ and David Matzas’ neutralizations techniques and Graham Macklins’ sciences of terror are used to justify extremist, violent behaviour and to radicalise new individuals. A qualitative text analysis was done on manifestos published by right-wing extremists between 2015 – 2019. The text analysis was applied to 3 manifestos written and published by Brenton Tarrant, Dylann Roof, and John Earnest. By coding the manifestos in Nvivo the result showed that between 36,39% and 42,11% of the texts were classified as attempts to either justify or incite violence. The similarities and discrepancies, in the rhetoric and rationalisation used by these individuals, were subsequently discussed and analysed in detail to see how they related to the theoretical framework. It was concluded that techniques of neutralization and sciences of terrors are used to a great extent within the chosen sample and that the use of manifestos should therefore be considered when discussing justification and radicalisation processes in extremist crime.