The horrendous crime occurred in China where a court heard the man had told friends he believed he was a psychopath.

Henry Chau Hoi-leung, aged 30, and his friend Tse Chun-kei, aged 36, are accused of killing Chau Wing-ki, 65, and his wife Siu Yuet-yee, 62, before dismembering, salting, and cooking them. Their heads and organs were discovered in two refrigerators on March 15 last year.

The other remains were found in a rubbish bin, cooked and packed into lunchboxes with rice to make it look like discarded food, in an attempt to hide the crime after the pair ran out of space in the fridges.

Chau claims to have killed his parents with the help of Tse in the middle of an emotional breakdown, but prosecutors allege that the murder was carefully planned.

Prosecutor Michael Arthur told the court that Henry Chau and Tse had planned the murders for more than three months, buying knives, refrigerators, microwave ovens, and a rice cooker.

The prosecutor said Chau admitted to friends that he had killed his parents and told them he was a psychopath in messages sent to a WhatsApp chat group while he was giving a statement at police headquarters in Wan Chai on March 14.

“I am a psychopath,” Henry Chau wrote in a message. “I cannot empathise with a normal person’s pain because of the experience of my childhood and adolescence.

“My process of emotion is different from a normal person.”

Chau told police after his arrest that he and Tse killed his parents on March 1 last year because “they felt ready”, the court heard. Both men have denied two counts of murder in court.

Chau initially told police his parents were missing after going to the mainland “to have fun”.

Police searched a flat at 38 Fuk Chak St in Tai Kok Tsui and found the dismembered bodies, as well as notes and receipts that suggested the pair had pre-planned the killings.

Prosecutor Arthur said: “Their crime was greatly premeditated. Their planning was extensive. Their preparation gathered pace in January and February. And on March 1 last year, they carried out the killings as they had planned.”

After his arrest, Chau told police he and Tse killed his parents, but that it was only Tse who cut up the bodies, treating it as though he was “chopping barbecued pork”, before packing the remains in rice boxes along with some rice and throwing out in the rubbish.

He said he killed his parents as they had no emotional connection.