Mark was barely 22 when this awful event occurred. The fact that he was at university establishes both lack of motive (he was due to move out in September 2009, so if he wanted to get away from home as the prosecution suggested all he had to do was wait; it doesn't make sense for him to throw his life away like this), and a strong alibi (Mark was living with his partner who recalled that they spent every night together).
"Samuel kept himself and his son apart. The picture is of the father and son living together in this house, more or less isolated from those who lived around and about him," Mr Price added. He said Mark commuted to lectures in London, caring for his "cantankerous" and "difficult" father, who had had a colostomy bag fitted in 2008.
Mr Alexander regularly boasted about Mark's academic achievements and intended for him to study at the University of Paris Sorbonne as part of his degree, without knowing that his son had no plans to take up the placement. Mr Price said: "The degree of control he exercised over his son, Mark, was disapproved of by others who observed it, and was resented by others whom it affected directly.
"For example, Senta Nazarbekova [Mark's girlfriend] described what she saw of the father-and-son relationship and how, as it seemed to her,
Mark struggled under the weight of his father's expectations and his control of him. On the face of this, it seems Mark did not, or possibly could not, resist. To Samuel, Mark would have appeared every inch the dutiful and obedient son."
In September last year, however,
Mark moved with Ms Nazarbekova to a flat in Fleet Street, central London, and told his tutors he could not go to France because his father was bed-bound. The prosecution alleges that it was likely by this time that Mr Alexander had already been killed.
During questioning by police, the accused insisted that his father was still alive. He claimed he had last seen him just before Christmas last year and his father was then living in a Christian community in London.
Mark Alexander denies murdering his father between 20 August 2009 and 5 February this year. He also denies unlawfully disposing of his body and two charges of perverting justice, by lying about his father's wellbeing and by dismembering his body and burying it in the garden.