Investigators are continuing to look for evidence at a property at Bungonia near Goulburn, close to 200km southwest of Sydney, allegedly attended by senior constable Beau Lamarre-Condon after the double killing.

NSW Police Commissioner Karen Webb said divers have finished their exploration of dams at the site, but officers were still conducting a line search in the area.

“We still believe that there is possibly evidence in that area that we don’t want to miss,” she said.

Lamarre-Condon, 28, has been charged with the murders of ex-Network Ten reporter Jesse Baird, 26, and boyfriend Luke Davies, 29, in Sydney.

Investigators believe he could have dumped the men’s bodies at the site, before returning later to move them to another, unknown location.

Webb said the crime scene was currently being treated as “anywhere between Newcastle and Bungonia and to the south of Sydney”.

“It is a massive area and without co-operation it is just old-fashioned police work to work through every single lead and every single piece of information to try and locate Jessie and Luke for their family,” she said.

Lamarre-Condon has been exercising his right to silence after receiving legal advice.

The senior constable is accused of using his police-issued firearm to kill the couple after entering Baird’s home in inner-city Paddington on February 19.

Police earlier on Tuesday confirmed a triple-zero call was made from Luke Davies’ mobile phone, rather than from Baird’s phone as previously reported, four minutes after neighbours heard gunshots at the house.

A patrol car was later sent searching for the source of the call, which was disconnected before anyone spoke.

But officers were unable to locate the user and did not attend Baird’s house at the time.

Investigators allege the crimes followed a months-long campaign of “predatory behaviour” by the charged officer, culminating in the fatal shooting.

Baird’s friend Isaac Muller said the former TV presenter and Lamarre-Condon were never in a relationship.

“Jessie briefly had an encounter with Beau,” he said.

“He was not his ex boyfriend … they never were going out.”

Police allege Lamarre-Condon acted alone but divulged “partial admissions” to others before handing himself in, having travelled more than 1000km from Sydney to Bungonia and Newcastle in a rented van during his attempts to cover up the crimes.

Independent state MP and former police officer Rod Roberts questioned how the 28-year-old former celebrity blogger ever got a job with the force.

“His background in chasing celebrities doesn’t sound like it’s a fit for the police force,” he said on Tuesday.

Roberts added Lamarre-Condon’s supervisors and senior officers should have picked up any issues “much earlier”.

Webb said a police investigation would work through any issues surrounding the senior constable’s employment with NSW Police, including his recruitment and assessments “to see if there are any red flags”.

1800 RESPECT (1800 737 732)

Lifeline 13 11 14

– AAP