As predicted by Marc Lépine in his suicide letter, some saw the event as the isolated act of a madman. A psychiatrist interviewed Lépine's family and friends and examined his writings as part of the police investigation. He noted that Lépine defined suicide as his primary motivation, and that he chose a specific suicide method, namely killing oneself after killing others (multiple homicide/suicide strategy), which is considered a sign of a serious personality disorder. Other psychiatrists emphasized the traumatic events of his childhood, suggesting that the blows he had received may have caused brain damage, or that Lépine was psychotic, having lost touch with reality as he tried to erase the memories of a brutal (yet largely absent) father while unconsciously identifying with a violent masculinity that dominated women. A different theory was that Lépine's childhood experiences of abuse led him to feel victimized as he faced losses and rejections in his later life. His mother wondered whether Lépine might have suffered from attachment disorder, due to the abuse and sense of abandonment he had experienced in his childhood.