But Chief McMahon's description of how this crime unfolded serves another purpose, and that is to emphasize just how easily someone who is suffering and poised to lash out can escape notice. Mr. McMahon revealed that Aguilar had told a primary care physician that he was hearing voices, and the doctor referred him for psychiatric treatment. The doctor told Aguilar's mother about it, according to police, but the mother said she didn't recall the conversation. Whatever the case, we often hear what we want to hear and see what we want to see. It likely would have been easy to look at Aguilar as a quiet young man somewhat adrift after high school, rather than to investigate whether he, as can happen to young people in late adolescence or early adulthood, was exhibiting the first signs of serious mental illness.