A jury has been asked if it could be a coincidence that a musician accused of killing a teacher, had earlier been looking at internet images of strangled women.
Jane Longhurst's body was found five weeks after she disappeared
Mr Coutts, of Waterloo Street, Hove, has admitted hiding and burning Miss Longhurst's body.
But he has denied murder, claiming she died during consensual sex.
John Kelsey-Fry QC, prosecuting, said such a claim was "an offence to common sense".
'Fantasies became reality'
The prosecution has alleged Mr Coutts murdered Miss Longhurst, who taught at a special needs school in Brighton, to act out a sexual fantasy.
Mr Kelsey-Fry reminded the jury during his closing speech that Mr Coutts had visited web sites advertising violent "snuff movies" the day before he is alleged to have strangled Miss Longhurst.
He told them: "Within 24 hours, by sheer accident on his account, his bizarre fantasies became reality literally in his own hands.
"That might strike you as being a coincidence that offends your common sense."
Graham Coutts admitted an obsession with pornography
Mr Coutts has told the court he checked on the body several times while it was kept at a storage unit before disposing of it by burning it on a common in West Sussex on 19 April, 35 days after Miss Longhurst died.
Mr Kelsey-Fry said: "On 14 March, Graham Coutts murdered Jane Longhurst by strangling her to death, taking an opportunity that arose to act out in reality his bizarre and macabre fantasies fostered on his computer."
Defence barrister Jeremy Gold QC suggested in his closing speech that the teacher may have fallen into the arms of Mr Coutts due to unhappiness in her life.
He said there was evidence she had been frustrated at work and was frustrated with her partner Malcolm Sentance.
Mr Sentance walked out of the court in response to Mr Gold's statement.
Mr Gold said: "Jane was at a particular time of her life when she needed some support that might have led to what happened at Graham Coutts' flat that day.
"It may be that Jane Longhurst needed someone that day and that it was Graham Coutts. It's just life.
"It does not make her a bad person, it just makes her human and it makes him human too."
The trial continues