The world’s most evil criminal duos
WERE they victims of a more powerful, abusive partner, or simply drawn together by their sick desires?
Whatever united these dire duos, it meant danger and death for those unlucky enough to cross their paths.
From the Australian couple whose relationship thrived on their shared interest in brutal sex, slavery and murder, to the crimes sprees of Bonnie and Clyde, these are some of the world's most dangerous criminal pairings.
The Lonely Hearts Killers
Raymond Fernandez and Martha Beck
Immortalised during a sensational murder trial and later in TV movies and films, Raymond Martinez Fernandez and Martha Jule Beck were an odd couple who killed women.
A pair described as "an American serial killer couple", they were dubbed "The Lonely Heart Killers" because of their M.O. of meeting their unwitting victims through "lonely hearts" newspaper ads.
A former navy and intelligence man, Fernandez claimed he was subjected to voodoo and black magic that gave him sexual power over women.
He met Beck, a promiscuous confused young woman addicted to romance fantasy, via a lonely hearts ad.
Fernandez initially only robbed female victims, and Beck - a somewhat willing slave - helped him.
But the two gravitated to murder.
Before being executed at Sing Sing Prison, New York, in March 1951, the pair professed their love for each other.
The Columbine High School gunmen
Eric Harris and Dylan Klebold
Eric David Harris and Dylan Bennet Klebold were two hateful and evil senior students at Columbine High School, in the US state of Colorado.
Best mates, they took up arms and committed a massacre on campus.
Their grand plan was to kill hundreds of students and emergency personnel with homemade explosive devices while shooting dead surviving students.
On April 20, 1999, the two friends - armed with an array of high-powered guns - marched through parts of the school and carried out their massacre.
In random fashion they shot dead 12 students and a teacher.
They wounded 26 other students.
Standing amid the carnage, Harris and Klebold counted to three and committed suicide in tandem.
In a journal later found by police, Harris had written: "Sometime in April (1999) me and V (Klebold) will get revenge and kick natural selection up a few notches.
"It'll be like the LA riots, the Oklahoma bombing, WWII, Vietnam, (violent video games) Duke and Doom all mixed together.
"I want to leave a lasting impression on the world.''
The Truro Murderers
Christopher Worrell and James Miller
Worrell and Miller were among Australia's first "tandem'' killers.
Responsible for the South Australian "Truro Murders", Worrell was a young charismatic sociopathic and Miller a homosexual drifter totally dependent on his friend for sex and support.
Miller was convicted in 1980 of murdering six of seven young women in the Truro case - Vicki Howell, 26; Deborah Lamb, 20; Tania Kenny, 15; Connie Iordandis, 16; Julie Mykyta, 15; and Sylvia Pittman, 16.
He was acquitted of the murder of the first victim, Veronica Knight.
Five bodies were found near Truro, 100km northeast of Adelaide, and another two recovered at Wingfield and Port Gawler.
Miller admitted helping to bury the victims but maintained Worrell - who died in a car crash a week after the final murder - was responsible for the rapes and killings.
Worrell raped and killed the women while Miller - who said at trial his job was to be "chauffeur and mug'' - waited nearby.
Miller died of cancer in jail in October 2008.
The Moors Murderers
Ian Brady and Myra Hindley
These Sick British lovers known as "The Moors Murderers" abducted, tortured and killed children and teenagers in Manchester between 1963 and 1966.
Ian Brady and Myra Hindley killed five - Edward Evans, 17; Lesley Ann Downey, 10; John Kilbride, 12; Pauline Reade, 16; and Keith Bennett, 12.
Young Keith's body has never been found and is thought to be buried on Saddleworth Moor, where the remains of three of the other victims were found.
Hindley died in prison in 2002.
Brady is serving a whole life term with no prospect of release.
At a mental health tribunal hearing in June last year, Brady dismissed his crimes as "recreational killing".
Butch Cassidy and The Sundance Kid
Robert LeRoy Parker and Harry Alonzo Longabaugh
Parker, who gained his nickname while working at a butcher's shop before taking on the surname of a former friend, became the leader of the Wild Bunch gang.
Into the gang he recruited Longabaugh, who'd spent time in jail in Sundance, Wyoming.
After a string of crimes, the two outlaws - along with Longabaugh's girlfriend - fled to Bolivia where it appears they were killed during a shootout in 1908.
Leopold and Loeb
Nathan Leopold and Richard Loeb
These two young American law students tried to commit the perfect murder in Chicago in the 1920s to prove they could do it.
The dominant one of the pair, it is believed Loeb used alcohol and sex to strengthen his bond with Leopold and coax him into committing petty crimes.
They started with theft and vandalism, breaking into a fraternity house at Loeb's old university and stealing items.
They burned down three buildings before stepping up to murder.
They coaxed a teen schoolboy named Bobby Franks into a car and bashed him to death.
They dumped his naked body in a drain and poured acid over his face and genitals.
The pair later confessed and were jailed.
Loeb was killed in prison.
Leopold was released after 33 years and died of a heart attack in 1971.
The Ken and Barbie killers
Paul Bernardo and Karla Homolka
Karla Homolka and her then-husband, Paul Kenneth Bernardo, kidnapped, sexually assaulted, tortured and killed two teenage girls in the early 1990s in Ontario, Canada.
Homolka, who videotaped the assaults, also drugged a 15-year-old girl so Bernardo could rape her in the basement of her family home after a Christmas dinner.
The teen victim choked and died.
Bernado was convicted of murder, sexual assault and dismemberment in the videotaped torture-slayings of young teens Leslie Mahaffy, 14 and Kristen French, 15, in April 1992.
Bernardo is serving a life sentence and will likely never be released.
The crimes horrified Canada.
Public anger was further fuelled by the lenient manslaughter plea-bargain deal Homolka struck in return for testifying against Bernardo.
After serving a 12-year sentence, Homolka told a local radio station she was remorseful and wished she had stopped the killings.
"I cry a lot. I can't bring myself to forgive myself … I didn't initiate the crimes. I followed."
Bonnie and Clyde
Bonnie Parker and Clyde Barrow
This young amorous couple ran rampant during the American Great Depression, committing hold ups on banks, stores and petrol stations.
Their gang is also believed to have killed police officers and civilians.
Police shot this couple dead, side by side, during an ambush in Louisiana in May 1934.
At the time of his death, Barrow was wanted for murder, robbery and kidnapping.
According to a US Department of Justice wanted poster, Parker "constantly" travelled with Barrow.
The pyromaniac and the outcast
Ottis Toole and Henry Lee Lucas
A sex victim and pyromaniac subjected to Satanic rituals as a child, Ottis Elwood Toole became an American drifter who was convicted of six counts of murder, after confessing to many more.
It was in 1976 when he met ostracised sociopath Henry Lee Lucas at a soup kitchen.
The two became lovers and, according to their later confessions, killed men and women and a young boy in a variety of ways.
Lucas, who liked to talk to police who gave him preferential treatment, confessed to hundreds of murders across 27 American states.
He was convicted of 10 killings.
Both men died in jail.
The House of Horrors couple
Fred and Rosemary West
Frederick Walter Stephen West had already killed at least two people before his second wife, Rosemary West, joined him and became an accomplice serial killer.
Over a 20-year period from 1967, he - and later Rosemary West - tortured and raped young women.
The couple were depraved in their sexual crimes.
They murdered at least 10 of their victims.
The shocking crimes were committed at their home in Gloucester, England, with West burying many of the bodies in the cellar and the garden.
The house became known as "The House of Horrors".
After being charged with 12 counts of murder in 1994, Fred West committed suicide.
Rosemary West was found guilty of ten counts of murder, including that of her 16-year-old daughter and eight-year-old stepdaughter.
She was jailed for life.
The Russell Street bombers
Stan Taylor and Craig Minogue
Charismatic career criminal Stanley Brian Taylor recruited young tearaway Craig Minogue at a youth group and, with a couple of other men, embarked on one of Victoria's most vicious armed robbery sprees.
It was a trail of violence that began in 1982 and culminated in the fatal bombing of police headquarters in Russell St in March 1986.
During the gang's holdups, Taylor and Minogue joyfully threatened men and women - and frightened children - with guns before robbing large amounts of cash, gold and jewellery.
Victims were bashed and a member of the gang sexually assaulted some female victims.
Taylor and Minogue hated police and, during their robbery spree, tried to blow up the Russell St police complex with a car bomb.
The blast killed a young constable, Angela Taylor, and injured many others.
Years later in prison, Minogue used weights in a pillow case to bash a fellow prisoner, killer Alex Tsakmakis, to death.
David and Catherine Birnie
This Australian couple forged a link through a shared interest in brutal sex, slavery and murder.
They committed their sadistic crimes in their suburban home in Perth, and the Gleneagles Forest at Wanneroo, north of the city.
The two were lovers when David Birnie was jailed for minor crimes in 1969 and, after separating, they came together again.
They never married but Catherine changed her surname by deed poll.
Beginning in October 1986 with Mary Neilson, the Birnies kidnapped four women and chained them up at their home.
The victims were raped and assaulted before their deaths.
Their bodies were dumped at the pine plantation.
A fifth woman refused a lift from the couple, and Catherine allowed a sixth woman to go free, leading to the pair's capture.
David Birnie hanged himself in his jail cell in 2005.
Catherine Birnie was jailed for life with a minimum term.
The Monsters of Belgium
Marc Dutroux and Michelle Martin
This Belgian couple were responsible for the kidnapping, rape and death of girls and young women - whom Dutroux imprisoned in his cellar.
In June 2004, Dutroux was sentenced to life imprisonment.
He'd been found guilty of leading a band of paedophiles and criminals to kidnap and rape six girls, killing four, in the mid 1990s.
The trial shocked Belgium.
Dutroux's ex-wife Martin was jailed for 30 years for her role as an accomplice.
In August 2012, Martin won parole to live in a convent.
In January this year, Dutroux wrote a letter from jail to the father of one of his victims in which he voiced no remorse and said he was the victim of a plot.
A criminal psychologist said the 40-page letter was "typical of the workings of a psychopath who is insensitive to the pain that he has caused''.