HONG KONG (REUTERS) - British banker Rurik Jutting needed the boost of cocaine to rape, torture and kill two Indonesian women in his luxury Hong Kong apartment and cannot shirk responsibility for their murder, prosecutors told a court on Friday (Nov 4) in closing arguments.

Jutting, 31, a former Bank of America Corp employee, has denied murder in the 2014 killings on grounds of diminished responsibility, but pleaded guilty to the lesser charge of manslaughter in a case that has caught the attention of the world.

His defence has argued that the former Cambridge University graduate had recognised disorders from cocaine and alcohol abuse on top of his other personality disorders of sexual sadism and narcissism, which impaired his ability to control his behaviour.

"He needed the boost of cocaine to give him the courage to rape, torture and ultimately kill," prosecution lawyer John Reading said, explaining that despite Jutting's disorders, his "mental responsibility was not substantially impaired".

The jury of five men and four women listened closely as Mr Reading presented his final arguments, giving several examples of Jutting acting rationally and calmly in between and during the killing of Ms Sumarti Ningsih, 23, and Ms Seneng Mujiasih 26.

He described Jutting's ability to form judgments and exercise self-control by trying to cut Ms Ningsih's neck as she knelt by the toilet bowl and later dragging her to the shower when he finished sawing her neck.

He detailed Jutting's plan to torture Ms Mujiasih with tools including a hammer and pliers from a hardware store, and his hiding of two knives.

"Let's be clear about these, I am going to use these to torture someone in the most inhumane way possible," Reading said, citing one of Jutting's self-made videos.

The prosecution said on Wednesday that Jutting acted rationally before and after the killings and had even telephoned his mother.

Jutting's defence, on the other hand, argued that the former British banker was "as far from normal as possible" at the time of the killings.

Once a "brilliant superman investment banker" earning several million Hong Kong dollars a year, Jutting spiralled out of control under the influence of personality disorders, defence counsel Tim Owen told the court.

He became "a bloated, unshaven, permanently intoxicated, isolated and depraved drug and alcohol addict whose mind was permanently obsessed about sadistic sexual fantasies," he said.

The past week has seen witnesses from both sides arguing the extent to which Jutting was impaired by multiple disorders.

Defence psychiatrists said Jutting was consumed by addictions to alcohol and huge amounts of cocaine, and suffered from narcissistic personality disorder and sexual sadism disorder.

Mr Owen argued that the picture painted by the prosecution that Jutting was cool, calm and collected at the time of the killings was untrue.

"Rurik Jutting was as far from normal as possible to be," he said. "He was off the scale... by any standard of normality".

The judge will sum up the case on Monday (Nov 7), with the jury expected to begin deliberating on the verdict on Tuesday (Nov 8).

Jutting, a former vice-president and head of Structured Equity Finance and Trading (Asia) at Bank of America, captured parts of his torture of Ms Ningsih on his iPhone. He also shot hours of himself discussing the killings, cocaine binges and detailed his violent sexual fantasies.

Parts of the footage have been shown to the jury during the trial. The courtroom has been constantly packed with international and local journalists due to the graphic nature of the killings in a city where such crimes are rare.

Sitting inside a sectioned off area in the courtroom, Jutting watched the arguments with a blank expression. He has attended the trial every day, escorted by three policemen each time.

The jury must decide whether the psychiatric and psychological evidence provided by the defence classifies the killings as manslaughter.

Murder carries a mandatory life sentence, while manslaughter carries a maximum of life though a shorter sentence can be set.

The defence has argued that Jutting felt huge stress during his working life, prompting him to binge on cocaine and alcohol which culminated in the killing and torture a year after he moved to Hong Kong.

He was drinking a bottle of alcohol every day and started consuming increasing amounts of cocaine. Jutting only worked for 10-15 days in the month before he was arrested and only worked a few hours per day.

Police have testified that they found Ms Ningsih and Ms Mujiasih's bodies in Jutting's high-rise apartment after he called them to report the killings. Ms Ningsih's mutilated body was found in a suitcase on the balcony, while Ms Mujiasih's body was found inside the apartment with wounds to her neck and buttocks.