A 21-year old male was arrested after killing a rival during a dramatic episode of violence, due to jealousy. The perpetrator was sent to prison, where he revealed, several months later, that he was using anabolic steroids at the time of the assault. The steroids were used to enhance his muscular mass. To document possible steroids abuse, a hair specimen (9cm in length, black in colour) was collected 7 months after the event and segmented in 3×3cm segments. A specific steroids screening procedure, involving both LC-MS/MS and GC-MS/MS, was used, which demonstrated the presence of drostanolone and its ester form, drostanolone enantate in the distal segment (i.e. the one corresponding to the period of the assault). Concentrations were 3 and 14pg/mg for drostanolone and drostanolone enantate, respectively. The etiology of this murder was finally considered to be due to an aggressive behaviour, which can have been enhanced by side effects due to anabolic steroids abuse.