A 29-year-old Sydney man feels disgusted after killing his own niece out of sexual attraction.

Derek Barrett previously pleaded guilty in the murder of 25-year-old Mengmei Leng, whom he stabbed multiple times in two days of torture last year.

The former IT worker also pleaded guilty to 21 offenses related to filming his niece to satisfy his sexual desires.

Leng, a Chinese university student, was found naked and lifeless inside a blowhole on the New South Wales Central Coast on April 24, 2016.

In a sentencing hearing on Wednesday, Barrett admitted to being attracted to Leng, who lived with him and her aunt for five years. He described her as a “pretty” girl.

Barrett told the New South Wales Supreme Court (via the Australian Associated Press):

“I betrayed my own family and hers for my actions.

“I disgust myself.

“She was a pretty girl.”

Investigations revealed that Barrett gagged and bound Leng in the morning of April 22, 2016, while his wife was away. He removed her clothes and took pictures of her body.

In the next two days, Barrett stabbed Leng several times. The victim died of a stab on her throat.

Barrett initially lied to authorities as he “couldn’t figure out what exactly happened until a little later.” He claimed he was on a drug binge before the crime.

Leng’s mother, 50-year-old Mei Zhang, wants Barrett sentenced to life. She told the court (via the Daily Telegraph):

“The dream of my life was completely broken down. I can still not accept that she was brutally murdered and that this thing had unlawfully detained Mengmei on the night of her murder and event took videos of the whole process.”

“I had only one child and according to the Chinese tradition that child will look after the parent as they grow older and now that this child’s gone my whole life is shattered.”

“No parent should be at the funeral of their child.”

The hearing continues.