Season 1

Carl Anthony Williams was a convicted murderer and drug trafficker from the Australian state of Victoria. He was the central figure in the Melbourne gangland killings. He was sentenced to life imprisonment with a non-parole period of 35 years for ordering the murders of three people and conspiracy to murder a fourth (which was unsuccessful)On 19 April 2010, while incarcerated at Barwon Prison, Williams was beaten to death with the stem of an exercise bike by another inmate, Matthew Charles Johnson

Backpacker Bloodshed, the first installment, is an unforgettable account of the gruesome Backpacker Murders that shocked Australia and reverberated around the world. It’s the story of serial killer Ivan Milat, who butchered seven young backpackers in the Belanglo state forest south of Sydney.

Abraham Gilbert "Abe" Saffron was an Australian nightclub owner and property developer who was reputed to have been one of the major figures in Australian organised crime in the latter half of the 20th century. For several decades, members of government, the judiciary and the media made repeated allegations that Saffron was involved in a wide range of criminal activities, including illegal alcohol sales, dealing in stolen goods, illegal gambling, prostitution, drug dealing, bribery and extortion. He was charged with a range of offences including "scandalous conduct", possession of an unlicensed firearm and possession of stolen goods, but his only major conviction was for tax evasion.

Kathleen Pettingill (born 1935) is the matriarch of the Melbourne based criminal family, the Pettingill family. Pettingill has one glass eye, having lost an eye after being shot through a closed door at the Collingwood Housing Commission of Victoria flats by Kim Nelson and Keryn Thompson as she and her son Dennis attempted to repay a $300 debt on behalf of her daughter, Vicky Having herself been a prostitute she then went on to run brothels herself.

Painter and docker, Les Kane was described by his widow as "the most violent man in Australia". Les' older brother, Brian was once Melbourne's top standover man, before he was gunned down. Mourners at his funeral included the entire Moran clan. Judi Kane speaks of how she fell for a man who had a hidden psychopathic streak.

George David Freeman was a Sydney organised crime figure and illegal casino operator. He was linked to the Sydney drug trade during the 1970s and '80s, was named in several Royal Commissions into organised crime and had links with American crime figures. Freeman served several prison terms for theft between 1951 and 1968 but was never brought to trial for any of his later alleged crimes, receiving only monetary fines for SP bookmaking in the mid-1980s. He survived a murder attempt in 1979, was married twice, and died in 1990 of asthma. Leonard Arthur ("Lenny", or more commonly, "Lennie") McPherson was one of the most notorious and powerful Australian career criminals of the late 20th century. McPherson is believed to have controlled most of Sydney's organised crime activity for several decades, alongside his contemporary Abe Saffron (who was dubbed "Mr Sin") and associate George Freeman.

David John Birnie and Catherine Margaret Birnie were an Australian husband and wife pair of serial killers from Perth, Australia. They murdered four women ranging in age from 15 to 31 in their home in the 1980s, and attempted to murder a fifth. These crimes were referred to in the press as the Moorhouse murders, after the Birnies' address at 3 Moorhouse Street in Willagee, a suburb of Perth, Western Australia.

John Travers and Mick Murdock were only boys when they cut their wrists and mingled their blood in a pact of loyalty establishing them as two of nations most despised killers.