The road worker and self-styled cowboy who called himself "Tex" had been in custody since 1994. He was diagnosed in May with terminal esophageal and stomach cancer. Milat died in Long Bay Prison where authorities sent him from a hospital last week to ensure he ended his days behind bars, officials said.
Milat was convicted of murder in the deaths of three German, two British, and two Australian backpackers after giving them rides while they were hitchhiking. The serial killings came to light when the mutilated corpses were found in a forest near Sydney over 14 months in 1992 and 1993.
His sentencing judge had described as "inevitable" Milat having had an unknown accomplice. Speculation has also persisted that he is responsible for other homicides and suspicious tourist disappearances.
Clive Small, a former detective who led the murder investigation, said on Sunday that he was confident Milat acted alone. But Small also suspects Milat had more victims, including three people whose bodies were found in other forests from as early as 1971.
"I had absolutely no respect for him at all. I thought that if he had one ounce of decency in him, he could have shown it before he died by admitting and clarifying a number of issues that are outstanding," Small said.
The case set off a frenzy of attention that consumed Australians like few others. Police put a team of investigators on the case, a reward was offered and media intensely covered the hunt for the killer and the possibility of more victims.
The crimes also inspired the "Wolf Creek" horror movies and television series released since 2005.
In September 1992, two runners orienteering in the Belanglo State Forest southwest of Sydney found a corpse hidden under broken branches and leaf litter. Police unearthed a second body nearby, and dental records confirmed the victims were Britons Caroline Clarke, 21, and Joanne Walters, 22, who'd been last seen in Sydney five months earlier.
Two more bodies were found in October 1993 by a man searching for firewood. Police identified them as Melbourne couple Deborah Everist and James Gibson, both 19, who'd gone missing in late 1989.
Police searches of the forest revealed the body of German Simone Schmidl, 21, and later in November the corpses of German couple Anja Habschied, 20, and Gabor Neugebauer, 21, who'd been missing since 1991.
Police established a 20-person team of detectives and analysts, posting a reward of 500,000 Australian dollars for information that would lead to the perpetrator. More than 300 police spent three months searching 3,800 hectares (9,400 acres) of forest.
Milat was arrested on May 22, 1994, following two months of surveillance. Police were aided by a British man, Paul Onions, who had accepted a ride from him while hitchhiking out of Sydney in 1990 and managed to escape from the car, running down the road while Milat shot at him.
Onions reported the attack to police at the time. But it wasn't until he contacted police again after learning of the serial killer investigation through the British media that detectives drew a connection and showed interest.
Small said Onions' identification of Milat as his highway assailant enabled police to execute search warrants targeting Milat.
A search of Milat's Sydney house found several weapons including parts of a rifle that matched one used in the killings, as well as camera, tent and a sleeping bag belonging to his victims. Milat had also given victims' property he had taken as souvenirs to family members.
When his trial ended in 1996, Milat was found guilty of seven murders and sentenced to serve seven consecutive life sentences.
Small said of Milat's death: "A lot of people are going to be very satisfied with the current outcome and will be pleased that it's over."
Ian Clarke, the Northumberland-based father of British victim Caroline Clarke, said: "No matter how Christian one might be, you can't help but be glad that this has happened."
Criminologist and author Amanda Howard corresponded with Milat almost monthly since 1997. She said Milat would never have made a deathbed confession.
"He died in a very painful way, but he was happy that he was able to take these secrets to his grave," said Howard, who suspects Milat has more than seven victims. She said Milat had recently written to her that "he felt for the parents of the German backpackers."
"He goes: 'I can't imagine what they must be feeling knowing that this and this and this had happened to their children,'" Howard said.
"But he then went into the graphic detail, so he enjoyed being able to relive that and retell that story," she added.
He was moved to maximum security solitary confinement after an escape attempt in 1997.
Milat continued to make headlines over the years through hunger strikes and self-harm, including severing a finger with a serrated plastic knife.
He had undergone specialist palliative care at a Sydney hospital for more than two weeks before he was returned to prison on Tuesday last week.
Corrections Minister Anthony Roberts said Milat had been sentenced to die in prison and authorities had ensured he did not end his days in a public hospital bed.
"He showed no remorse. We ensured the sentence was carried out," Roberts said. "He can rot in hell."
Milat was born on Dec. 27, 1944, fifth of 14 children of a Croatian immigrant father and an Australian-born mother.
In a recent television interview, an older brother summed up Milat's infamy.
"He was going to kill somebody from the age of 10," Boris Milat said. "It was built into him. He had a different psyche. He's a psychopath, and it just manifested itself with, 'I can do anything, I can do anything.'"
Karen Milat described her former husband as a "gun nut" who shot and knifed kangaroos in the forest where his victims were found.
He a cat called Gizmo, loved his Harley-Davidson motorcycle and relaxed by painting model trucks and planes in camouflage colors, she said.
Milat's gruesome legacy continued in 2010 when his great-nephew, Matthew Milat, lured his 17-year-old friend into the Belanglo forest and murdered him with an ax.
The then 17-year-old Milat, who was sentenced to 43 years in prison for the murder, boasted to a friend a day after his crime: "You know me, you know my family. You know the last name Milat. I did what they do."