Laurent Bonomo's father, Guy, has explained the effect of his killing on the family, in a statement read to the Old Bailey.
Laurent was born on 9 October 1984 and you took the decision to end his life on 29 June 2008.
Laurent Bonomo with his 10-year-old sister, Ambre
You were not satisfied with breaking in and stealing his computer a week before you killed him. After the burglary, Laurent was terrified. He cried on the phone to me and I tried to comfort and reassure him.
It was then that I realised that although a young man, he was still my little boy.
I explained to Laurent that he'd grown up in a sheltered student environment and was naïve about the outside world. He was easy prey to people like you.
I told him to be vigilant at all times. He needed to grow up quickly if he was going to marry and have children with his fiancée Marie.
We have sat in court for the last six weeks, hoping for answers, trying to find out what happened to our children. But you have lied in court and have refused to tell the truth. This is what we have been waiting for.
Without knowing what happened that night and why, we cannot move on and find peace. I ask you again, Why?
You know the atrocities that you have committed. Your attitude and apparent lack of remorse shows us that you have no conscience at all. Tell me why you have done this? I need to have answers.
For the last 11 months, I have been forced to speak about Laurent in the past tense, when all I could see for him was a bright future.
Laurent was a fantastic boy. From the day he was born, he brought happiness to friends and family. He was kind and loved life. You took him away from those that loved him deeply. Do you know the meaning of love?
Laurent adored his parents and not only are we suffering, but also his 10-year-old sister, Ambre. Laurent was her big brother and her hero. He was the one who looked out for her and protected her.
She was so proud when she talked about him to her friends and it is unbearable to watch her suffering and struggling to cope with her loss.
Laurent came from a large family. He had 10 cousins and he was the eldest and the one that everyone looked up to. Every Christmas, we would gather together as a family, only last Christmas, he was not there. Their leader and hero was gone.
Before Laurent came to London, he and Marie took part in a civil ceremony to cement their relationship. They were planning their future together. Her life has now stopped.
Laurent had many incredible friends who loved him dearly. Not only have you taken Laurent's life, you've taken my heart and soul. I need to try to learn to live without my son, to try and live a normal existence and try to forget the torture you inflicted upon him, but I am tormented by images of his suffering.
Laurent's little sister is aware that I am here in London for the trial and she has asked me if the bad people who did this to her big brother will be punished. Her mother and I have told her that they will go to prison for a long time and will not be able to hurt anyone else, she replied with a big smile. For her you represent evil.
I wish from the bottom of my heart that you will stay in prison for the rest of your lives. I can't bear to think that someone so evil will walk the streets again, that my daughter or a member of my family could encounter you again.
I appeal to you as Laurent's father to have a conscience. To end our misery and suffering by one day telling the truth about our son's final hours.