Horror details emerge of Michelle Leng's final moments before she was 'murdered'.

Mengmei ‘Michelle’ Leng’s horrific final moments before her murder have been revealed as police thrust an additional 27 charges on her accused killer uncle.

The 25-year-old university student’s naked body was found with more than 30 stab wounds floating in the Snapper Point blowhole on the NSW Central Coast on April 24.

Police charged Derek Barrett, 27, later that month with the murder of his niece, who he lived with, in what investigators described was a “very violent attack”.

Detectives laid the extra charges on Barrett today at Burwood Local Court. It is alleged they discovered images of Leng naked with duct tape tied around her wrists and strapped over her mouth, Fairfax Media reports.

Police say the photos were found on a phone linked to Barrett.

Barrett is also accused of photographing a sleeping child and of filming himself masturbating over the young girl and Leng on several separate occasions prior to Leng’s death.

Barrett's additional charges include five counts of committing an act of indecency, 17 of filming a person's private parts without consent and two of installing a device to film.

He is also charged with two counts of filming a person in a private act without consent and of detaining for advantage.

CCTV at Campsie train station shows the last time Michelle Leng was seen in public on April 21. Post continues after video...

Earlier, Police found CCTV footage showing a car driving into the Lake Munmorah national park on the morning her body was found.

It has been claimed Leng's cousin came home two days before unaware that Leng was being kept captive upstairs.

Barrett, a former IT worker, is married to Leng's aunt who was in Wollongong at the time of Leng's alleged murder.

Leng moved to Australia five years ago from China to study at the University of Technology, Sydney.

Her mother Mei Zhan, who lives in Chengdu, flew to Sydney in May and made impassioned plea for justice.

“You can never imagine how painful it is for me," she said.

The case returns to court on August 10.