Urgent search for husband of woman found dead in Sydney bushland resumes as police investigate suspicious car

CCTV of a car has become crucial in the search for the missing husband of a woman found dead in bushland in the Sydney suburb of Botany last week.

The body of Zhuojun 'Sally' Li, 33, was found in bushland at Sir Joseph Banks Park in Botany on December 9 after being reported missing last month.

There has been no sign of her husband Jai-Bao 'Rex' Chen, also 33, who remains unaccounted for, and an urgent police search has resumed today.

READ MORE: Survivor Louisa still thinks about the nightmare Sydney siege every day

The NSW homicide squad have zeroed in on a vehicle captured on CCTV along Foreshore Road in Botany.

It's believed this car may have transported Li's remains to the site where she was found.

Police say the car is not registered to either Li or Chen, which may suggest a third party is involved.

"We have to keep an open mind, and when we do that we look at the possibility of a third party," Homicide Squad boss Danny Doherty said.

"Not only in the suspected murder of Sally, but we also have to look at a third party being involved in the disappearance of Rex as well."

READ MORE: Battle brewing between two of Australia's oldest pubs

This car has become the major line of inquiry being explored today as police work to locate Chen.

Police released images of the car, a Toyota Avensis, asking for information about its movements and whereabouts.

Both Li and Chen have not been seen alive since November.

Doherty said yesterday detectives held "grave concerns" for Chen's safety and wellbeing.

The couple were known to live in Greenacre, near Bankstown in Sydney's south-west.

"Truth be told… we're not sure whether Rex is alive or dead," Doherty said.

"It's a question mark on whether he's a person of interest or a victim, we still don't know."

Doherty said there were no reports of any domestic violence between the couple or any links to organised crime.

Police are asking anyone with information about Chen's whereabouts to contact Crime Stoppers.

Chen is described as being of Asian appearance, 165cm to 170cm tall with a slim build, black hair and brown eyes.