He sang at his family's funeral. He was also their killer.

“Sorry I never told you all I wanted to say…

“Now it’s too late to hold you ’cause you’ve flown away, so far away

“Never had I imagined living without your smile…”

Standing before three caskets, Sef Gonzales’ voice rang through the church as he sang, eyes closed, the Mariah Carey/Boyz II Men song ‘One Sweet Day’ at his family’s funeral.

His parents — Teddy, 46, and Mary Loiva, 43 — and his younger sister, Clodine, 18, had been brutally murdered at their home in the quiet suburb of North Ryde in Sydney just a week prior on July 10, 2001.

Listen to the lead investigator of the Gonzales' investigation discuss the case on True Crime Conversations. Post continues afterwards.

It was Sef who had found their mutilated bodies that night. He’d returned home from dinner with a friend just before midnight to an eerily quiet and dark house. He opened the door to horrific scenes.

There was blood everywhere. His parents’ bodies lay in the living room — his mother’s throat slashed, his father’s spinal cord severed and body covered with frenzied stab marks. His sister was still in her bedroom upstairs, clearly caught unaware as the killer approached from behind, strangling, stabbing and bludgeoning her with a baseball bat.

Spray-painted across the white walls of the Gonzales’ dream home, where the devout Catholics family’s altar to Our Lady Queen of Peace watched over them, was the racist slur: “F**K OFF ASIANS. KKK.”

The Gonzales family - Sef (with face covered) Mary, Clodine and Teddy. Image: AAP/NSW Police Media.

Crown prosecutor Mark Tedeschi, QC, later said of the triple-murders: "This was not a professional killing, it was a slaughter by an angry amateur who wanted to make absolutely sure of their deaths."

"Vastly more force was used than was necessary," he added.

'A lot of inconsistencies'. How the case unfolded.

Nick Kaldas, a former Australian police officer who led the murder investigation, told Mamamia's True Crime Conversations the scene was "truly savage".

Days after the gruesome massacre, 20-year-old Sef made a tearful appeal on television asking for the killer to come forward.

He even offered a $100,000 reward for any information.

"It is difficult to explain the love and ties in my family... but if you were to picture the four corners of the world, in my world we were the four. The three corners of my world are now gone," he said, overcome with grief, at a police conference at the time, reported Sydney Morning Herald.

Sef Gonzales as he made the plea for help to find his family's killer. Image: AAP/Dean Lewins.

But, as the head of NSW's Homicide Squad, Nick was watching closely. And he noticed something telling about Sef's public display of grief: "My memory is that there were no tears, there were actions, but no tears."

Within three days of his family's murder, Sef had contacted his father's accountant to find out how much money his parents were worth.

According to the Sydney Morning Herald, in the following months, he unabashedly lived a life of luxury — moving into an expensive new apartment, putting down deposits on high-end cars, telling dealers he was expecting a large inheritance soon.

He sold his parents’ cars against the wishes of his grandmother, and even tried to pawn his mother's jewellery. He pestered his relatives in the Philippines, who handled the family’s affairs, for money.

"It's sort of shameless," Nick said. "It's the only word I can think of."

Investigators soon discovered that the eldest Gonzales child’s life was "unravelling" before his eyes.

When his strict and demanding parents, who’d always dreamed their son would be a prestigious doctor or a high-powered lawyer, found out he was failing out of his pre-law university course - and that he had created fake academic transcripts to deceive them - they took away Sef’s car and his generous allowance. They threatened to disown him.

His mother also disapproved of the girl he loved, telling Sef a few days before the murders he would not be welcomed in the family if he continued to see her. They’d sent Clodine to Melbourne to finish her studies when they discovered she was dating a man they deemed unsuitable.

What we know about the crimes of Sef Gonzales. Post continues after video.

So, Sef began concocting a plan to get his parents off his back and his hands on his family's entire $1.5 million estate.

He began searching online "methods of killing" and quickly focused in on "poisoning".

"The only conclusion that can be drawn is that he was exploring ways to do it in a way that he wouldn't get caught if it was done by stealth," Nick said of Sef's internet search history.

He purchased highly toxic seeds from Byron Bay and the United States. He wrote letters to a food company, the AFP and the Australian Quarantine and Inspection Service in an elaborate ruse to cover his tracks, pretending to be a disgruntled employee claiming "three of [your] products have been poisoned".

But his poisoning plan failed. His mother fell ill with suspected food poisoning but returned home from hospital the next day.

Ten days later, Sef progressed to murder.

His carefully planned alibi soon fell apart. Neighbours had heard noises coming from the Gonzales house that night; a client of his father had dropped by and saw Sef's green Ford Festiva in the carport, with the distinctive number plates of SEF80G.

The racist graffiti also didn't add up. "It was incongruous. It just didn't fit, as was most things in that case," Nick said.

The other lies he had spun to his friends and family also collapsed once police began investigating. He had told friends he had cancer, that he was dying, that he needed money for treatment. He claimed he was offered a record deal after singing at his family's funeral. He bragged to a girlfriend once that a prostitute said he was so good in bed that he didn't need to pay. A fan page dedicated to Sef Gonzales, which he said was created by a grateful friend, turned out to be run entirely by himself.

"He lived a sort of fantasy life, if you like, where he bragged about things and claimed things and simply went through and all of that came back to haunt him," Nick said.

"There were a lot of inconsistencies in what [Sef] said…. He lied. He tried to change his version a number of times, and it just got worse and worse for him. Every time he opened his mouth, he basically dug a deeper hole for himself. He was never going to survive this."

Eleven months after Sef walked in on his massacred family, NSW Police arrested him and charged him with three counts of murder.

Despite the mounting evidence against him, Nick noted "there was a certain amount of arrogance and sort of haughty behaviour thinking, you know, I'm going to beat this. Nothing's going to happen to me".

But, on September 17, 2004, a day after his 24th birthday, Sef was sentenced to three concurrent life sentences without parole for the murders of his family.

In November 2007, he appealed his conviction, but it was dismissed.

To this day, he still maintains his innocence.

"I don't recall anyone saying he was remorseful. If he was, he would have pleaded guilty," said Nick.

This article was originally published in April 2019 and has since been updated.