But it soon disconnected, before any words could be understood on the other end, granting the alleged killer several days to cover up the crime.
After allegedly shooting dead Jesse Baird and his new boyfriend Luke Davies in a Sydney home, senior constable Beaumont Lamarre-Condon clocked up more 1000km visiting family, friends and a rural property before handing himself in four days later.
His alleged cover-up and subsequent silence left baffled police on Monday searching waterways to try to uncover the dead men's remains.
"It is our number one priority at this moment to try and locate Jessie and Luke to give the family some solace and be able to come to terms with what's occurred," Deputy Commissioner David Hudson told reporters.
Despite their suspect's silence, police on Monday detailed their understanding of the double homicide on February 19 including the minutes after witnesses heard but dismissed the fatal shots.
Four minutes after shots were heard about 9.50am, a triple-zero call emanated from Mr Baird's phone.
But "no communication" was made before it disconnected before anyone spoke, Mr Hudson said.
Lamarre-Condon - the first serving NSW police officer charged with murder in several decades - then allegedly used the same phone for the next 38 hours to pose as the deceased to throw loved ones and investigators off track.
In one message, the 29-year-old's flatmates were told to put his possessions in storage or sell them for cash after conjuring a fiction about Mr Baird immediately moving to Perth.
Lamarre-Condon, whose on-and-off relationship with the TV presenter ended in late 2023, also allegedly made attempts to clean the crime scene before hiring a van to move the bodies.
While he appears to have acted alone, the serving officer met up with several people including an "innocent friend" who unknowingly assisted him when the bodies were disposed of, Mr Hudson said
A police crime scene was set up at the property on Hazelton Rd, Bungonia. (Mick Tsikas/AAP PHOTOS)
The woman bought a handheld angle grinder and accompanied Lamarre-Condon to a rural property with several dams on February 21 almost 200km southwest of Sydney.
As she stood by the gate, she watched him drive inside, return 30 minutes later and drive her back to Sydney.
But detectives doubt the deceased men's bodies remain at the Bungonia property, near Goulburn.
Lamarre-Condon made a second trip later that night, after buying weights from a department store.
His return trip to Sydney precedes a large gap in the police timeline.
"It would appear that the accused was suspicious of the acquaintance that attended with him and about her belief that what he might have been up to, and very likely may have returned to those bodies later that evening," Mr Hudson said.
A small boat was removed during the police search of the property at Bungonia. (Mick Tsikas/AAP PHOTOS)
The acquaintance was not a suspect and did not know that two bodies were allegedly in the back of the hired white van.
Lamarre-Condon also made contact with family members and police were relying on their assistance as part of the investigation, Mr Hudson said.
In one instance, the senior constable turned up in Newcastle asking a friend to hose his hired van.
It allegedly followed a months-long campaign of "predatory behaviour" after Mr Baird and the officer's on-and-off relationship ended poorly in late 2023.
Detectives believe Lamarre-Condon recently used a key to enter Mr Baird's Paddington home.
"We believe that he took possession of Jesse's phone and deleted contacts and messages out of that phone before leaving the premises," Mr Hudson said.
Lamarre-Condon, who joined the police force in 2019, is in custody after not making a bail application on his initial court appearance for the twin murder charges.
The couple's disappearance was deemed suspicious when blood-stained possessions belonging to them were found in a skip in the southern Sydney suburb of Cronulla on Wednesday.
Officers are working 'around the clock' to find the men's bodies, the police commissioner says. (Mick Tsikas/AAP PHOTOS)
The discovery led police to Mr Baird's blood-smeared share house, about 30km away.
Mourners continue to lay floral tributes outside the Paddington terrace where police allege the murders took place.
1800 RESPECT (1800 737 732)
Lifeline 13 11 14
8°C