Ground search for clues on woman's suspicious death

Stormwater drains, abandoned worksites and roadside rubbish bins have all been searched thoroughly by investigators hoping to find crucial evidence in the suspicious death of a woman in Sydney's west.

Dozens of officers were seen scouring the area surrounding the Merrylands apartment where Erin Gilbert was found dead on Sunday night.

The 42-year-old was discovered in the living area of her Newman Street unit after neighbours called police about 11.30pm to report concerns for her welfare.

Police have since described the death as suspicious and launched an investigation under Strike Force Trevelyan.

On Thursday officers conducted line and ground searches as the hunt to uncover information continues. 

Footage shared by NSW Police showed investigators probing public parks, peering beneath caravans and vehicles and searching abandoned worksites and rubbish skips. 

A group of officers were seen opening and examining the inside of stormwater drains as well as appearing to mark various objects along the suburban streets. 

Other officers attached to South West Metropolitan Region Operational Support Group were seen scouring piles of rubbish and traversing long grass and overgrowth as residents watched on.

Reflective mirror devices were also used to glimpse inside the backyards of nearby homes.

Local police commander Superintendent Andrew Holland told reporters on Tuesday that while Ms Gilbert had been seriously injured, her cause of death was not yet known.

"The injuries (were) very serious and severe. Unfortunately, we don't know the exact cause of death at this point," he said.

Her husband said he tried to resuscitate his wife and perform CPR before police officers arrived.

"(I) walked into the biggest f***ing nightmare," Nic Gilbert, 38, told media on Wednesday.

"I walked through the bedroom, Erin was on her back and it looked like she was choking on blood."

Mr Gilbert was taken to Granville Police Station for questioning and released without charge.

"He hasn't been ruled in or ruled out at this stage," Supt Holland said on Tuesday.

Police are appealing for help from the public to establish a timeline in the case.