In this article, the case of Mr Holmes is discussed in detail with a particular focus on the treatment he received when he was at graduate school in the months leading up to the shooting and, primarily, the findings from the sanity evaluation carried out by Dr Metzner. In this chapter the I 3 model is applied to the case of Mr Holmes. His attack can be seen as resulting from an increase in dispositional and situational impelling factors and a decrease in inhibiting factors, based on a detailed review on available information, the instigation, impellance and inhibition factors potentially present during the lead up to the shooting (approximately five months) and present at the time of the shooting. Instigation factors included a breakup with his girlfriend and academic failure at graduate school. Impellance factors included chronic (i.e., persistent) and severe mental illness associated with psychotic features (e.g., delusions, hallucinations and disordered thinking); social anxiety disorder (and trichotillomania); chronic suicidal thinking; chronic homicidal thinking and his perceived biological shortcomings. Inhibition factors included experiencing a "loss of fear" or "overcoming fear" of the consequences of killing people; prescription medication which may have increased his inhibition (specifically, antidepressant medication, sertralinehe was eventually prescribed 150 mg of sertraline) and individuals with ASD may be 'more readier' compared to others to act on psychotic impulses. This may have been what was happening in the case of Mr Holmes why he was potentially more vulnerable to acting on his psychotic ideas and beliefs. Also, inhibition caused by his severe mental illness associated with psychotic features (later diagnosed by the four psychiatrists before the trial as either schizophrenia, schizoaffective disorder and schizotypal personality disorder).