As Son Thanh Nguyen lay in the lounge room of a Canley Vale home, blood dripping from his mouth and hog-tied with cable ties, a female drug lord allegedly handed a case of $50 notes over to Condell Park man Kevin Ly.
Mr Ly was the woman's henchman, police will allege, and carried out grisly duties for her as she ran a methylamphetamine empire across Sydney's south-west suburbs.
More News Videos
Man charged over couple's murder
RAW VISION: A man has been charged over the alleged murders of a couple whose bodies were located separately in Sydney's south-west in 2013 and 2014.
The money was to finish off the man who lay bleeding in front of them, and his innocent girlfriend in the nearby room, on the night of April 10, 2013.
"Just do it," she allegedly said, according to a witness who was present.
More than three years later, homicide detectives made a major breakthrough in the double-murder investigation on Monday, arresting Mr Ly, 25, during a traffic stop in Merrylands.
The chilling level of brutality involved in the killings was revealed for the first time in police documents tendered in Fairfield Local Court on Tuesday.
The documents reveal that two men present during the killings have since rolled over to become star witnesses, blowing open the syndicate's alleged dealings.
Police believe Mr Nguyen, the syndicate's drug cook, made the fatal mistake of stealing the ice he had cooked in the Canley Vale home and drug lab on April 9, 2013.
![Police said Thi Kim Lien Do begged for her life when duct tape was briefly removed from her mouth.](/web/20160922013243im_/http://www.watoday.com.au/content/dam/images/g/r/k/c/9/q/image.related.articleLeadwide.620x349.grk8j0.png/1474421326546.jpg)
He staged a break-in at the small fibro house that night and took about 10 kilograms of the drug.
Mr Nguyen, 39, was the only one in the syndicate with the skills to make the drug, yet he had a reputation for stealing his own product and was constantly guarded at work, police allege.
![Police arrest Kevin Ly on Monday over the alleged murders of drug cook Son Thanh Nguyen and girlfriend Thi Kim Lien Do.](/web/20160922013243im_/http://www.watoday.com.au/content/dam/images/g/r/k/a/5/v/image.related.articleLeadwide.620x349.grk8j0.png/1474421326546.jpg)
His boss, the female drug lord, suspected him immediately and mobilised a group of men, including Mr Ly, to lure him to the lab the next day.
Mr Nguyen, known as Sonny, made the fatal mistake of bringing his girlfriend Thi Kim Lien Do, 35, who police will allege was also murdered as collateral damage.
![Police believe girlfriend Thi Kim Lien Do was collateral damage.](/web/20160922013243im_/http://www.watoday.com.au/content/dam/images/g/r/k/a/t/i/image.related.articleLeadNarrow.300x0.grk8j0.png/1474421326546.jpg)
When the couple arrived, Mr Nguyen was chased into the garage, pistol-whipped by Ly and hog-tied, police will allege.
Ms Do was tied up in a bedroom and suffocated with a pillow.
![Son Thanh Nguyen's body was found on the side of the road in Bankstown in 2013.](/web/20160922013243im_/http://www.watoday.com.au/content/dam/images/g/r/j/x/m/9/image.related.articleLeadNarrow.300x0.grk8j0.png/1474421326546.jpg)
The pair repeatedly denied stealing the ice and Ms Do begged for her life.
"Please forgive me. I didn't do anything. I know nothing. Please don't kill me," Ms Do allegedly screamed as duct tape was briefly removed from her mouth.
Mr Nguyen was dragged into the lounge room and given one last chance to confess, police allege.
"Return it. If you return it [Ms Do] will stay alive. If you did it you have to bear the consequences," the female syndicate boss allegedly said.
When he denied stealing the drugs, the woman allegedly handed Mr Ly a wad of cash and allowed him to strangle Mr Nguyen to death with a garden hose while his mouth was stuffed with wet cloth.
His body was found wrapped in sheets and dumped on a footpath in Bankstown that night.
Nine months later, two men repairing a fence on a block near Flynn Avenue in West Hoxton came across Ms Do's decomposing body in bushland.
After the alleged murders, police say the group reconvened at Hungry Jack's in Cabramatta where Mr Ly allegedly laughed about the killings.
"Kevin told us it's our turn to dump [Ms Do's] body. Kevin was laughing when he was talking to us," one of the roll-over witnesses allegedly said.
Hundreds of call records have placed those involved at key locations at particular times, helping to build a detailed and exhaustive police case.
Mr Ly smiled at supporters in Fairfield Local Court and didn't apply for bail.
On Tuesday, police said they expected to make more arrests in the coming days yet they urged those involved to hand themselves in beforehand.