Vincent Tabak saw the fear in Joanna Yeates's eyes as she struggled for her life, but refused to stop strangling her until she died, Bristol Crown Court was told yesterday.
In his closing remarks, Nigel Lickley, for the prosecution, said Tabak, a 33-year-old Dutch engineer both taller and stronger than his victim, had been in full control that night; with sex on his mind; he had intended to kill or harm Ms Yeates.
Pointing out the discrepancies in Tabak's original defence statements and his evidence in the witness box during the murder trial, Mr Lickley described the defendant as a "deceitful liar" who had covered up his crime in a cool and detached way. In giving evidence, he had answered "can't remember" to more than 80 questions.
Tabak, who admits manslaughter of Ms Yeates, a 25-year-old landscape architect, but denies murder, stared at the floor, his head in his hands, during the QC's closing speech.
"The whole incident is linked to sex. This is a killing linked to sex," said Mr Lickley.
During the three-week trial, the jury heard how Ms Yeates had been strangled after returning home from drinks with colleagues on 17 December last year. Mr Lickley said she suffered 43 injuries in the struggle for her life.
A missing persons hunt was launched on the Sunday when her boyfriend Greg Reardon got back and telephoned the police but, on Christmas Day, a couple out walking their dog found her body three miles from her home in Clifton, Bristol.
"He knew she was struggling and fighting, he knew she was in pain, he knew she was frightened, he knew she couldn't breathe," said the barrister. "Instead of letting go and releasing his grip and letting her live, he carried on and on and on until she went dead in his hands."
Strangulation was not a "spur-of-the-moment" crime, he added. He said Tabak's behaviour after the killing was not that of someone in panic, as he had suggested in evidence, but of someone who was "cool", "calculating" and "detached" – intelligent and able to deceive his own girlfriend, Tanja Morson, without giving away any trace of emotion. In conclusion, Mr Lickley said: "He could have at any point released his grip and walked away. He chose not to. Joanna Yeates had no choice in the matter."
William Clegg QC, defending Tabak, said: "I am not going to ask you to excuse his conduct after the killing – there can be no excuse."
Calling Tabak's behaviour "dreadful", he urged the jury to base its verdict on the evidence, which he insisted did not back up the prosecution's assertion that Ms Yeates's death was "planned, premeditated and sexually motivated".
"I am going to invite you to conclude this was a very short, fast-moving incident which would have been over in less than 30 seconds," Mr Clegg said, adding: "There was a few seconds of madness."
The trial continues.