Pigfarmer

Robert William "Willie" Pickton (born October 26, 1949) of Port Coquitlam, British Columbia, Canada is a former multi-millionaire pig farmer and serial killer convicted in 2007 of the second-degree murders of six women.He was also charged in the deaths of an additional twenty women, many of them from Vancouver's Downtown Eastside, however these charges were stayed by the crown in 2010. In December 2007 he was sentenced to life in prison, with no possibility of parole for 25 years—the longest sentence then available under Canadian law for murder.

During the trial's first day of jury evidence, January 22, 2007, the Crown stated he confessed to 49 murders to an undercover police officer posing as a cellmate. The Crown reported that Pickton told the officer that he wanted to kill another woman to make it an even 50, and that he was caught because he was "sloppy".

http://criminalminds.wikia.com/wiki/Robert_Pickton

Snowtown

The Snowtown murders (also known as the bodies-in-barrels murders) was a series of homicides committed by John Bunting, Robert Wagner, and James Vlassakis between August 1992 and May 1999 in South Australia. A fourth person, Mark Haydon, was convicted for helping to dispose of the bodies. The trial was one of the longest and most publicised in Australian history.

Only one of the victims was killed in Snowtown, which is approximately 140 kilometres (87 miles) north of Adelaide, and none of the eleven victims nor the perpetrators were from the town. Though motivation for the murders is unclear, the killers were led by Bunting to believe that the victims were pedophiles, homosexuals or "weak". In at least some instances, the murders were preceded by torture, and efforts were made to appropriate victims' Centrelink social security payments and bank funds.

http://en.wikipedia.org/wiki/Snowtown_murders

Shipman

Harold Frederick Shipman[2] (14 January 1946 – 13 January 2004) was a British doctor and one of the most prolific serial killers in recorded history.
On 31 January 2000, a jury found Shipman guilty of 15 murders. He was sentenced to life imprisonment and the judge recommended that he never be released.

In March 1998, Dr Linda Reynolds of the Brooke Surgery in Hyde, prompted by Deborah Massey from Frank Massey and Son's funeral parlour, expressed concerns to John Pollard, the coroner for the South Manchester District, about the high death rate among Shipman's patients. In particular, she was concerned about the large number of cremation forms for elderly women that he had needed countersigned. The matter was brought to the attention of the police, who were unable to find sufficient evidence to bring charges.

Shipman died on 13 January 2004, after hanging himself in his cell at Wakefield Prison in West Yorkshire. His suicide occurred one day before his 58th birthday.

http://en.wikipedia.org/wiki/Harold_Shipman