How do you begin to understand that your child has been responsible for a tragedy of this magnitude? Like Eva Khatchadourian, the mother of the killer in Lionel Shriver’s novel We Need to Talk About Kevin, Terri has combed through every detail, every nuance, every memory, every clue, to try to work out what in her eldest son’s past could have made him walk into that schoolhouse that day. “What did I miss?” she asks in her newly published book. “I was — always will be — his mother. Surely if anyone could spot signs of trouble it would be the woman who gave birth to him. At what point did bitterness begin to seethe beneath the surface contentment? Or hate tug harder at the mind and heart than love?” …

As a mother, she says, she cannot stop loving her son — and as she unravels his story — the ordinary story of an ordinary boy in an ordinary town whose life ended so violently — you feel she is doing what any parent can and must do, even in the face of odds as great as these, which is to see the very best in her child, to give him the benefit of every doubt, to put every tale in the most sympathetic light. Yet, when she has finished describing how sweet a baby he was, and how he had to cope with being born with club feet, and his learning difficulties, and the loss of his first child soon after her birth, the question hangs in the air between us, and Terri is brave enough, through her tears, to name it and answer it herself. “I ask myself, were these things related to what happened? But the truth is that plenty of people in the world have experienced extreme pain and suffering, and have coped with it. They didn’t go on to commit terrible crimes like Charlie did.”

Read the article “My Son, the Mass Murderer: ‘What Did I Miss?’” on theguardian.com.