William Horncy was born in 1954. He grew up in Bournemouth, a coastal town in England. Horncy later lived in Bridport, another town in Dorset. He worked as an accountant before he became involved in criminal activities. In 1999, Horncy was sentenced to prison after admitting that he provided fake identities to international criminals.

Horncy's early life before his criminal activities did not have any widely reported incidents. However, his later actions led him into the criminal underworld. He was involved with a group that sought to take over a successful freight company in London, which was owned by a millionaire named Amarjit Chohan. Horncy's life took a darker turn as he became associated with drug dealing and other crimes.

He initially gained notoriety when he was implicated in major crimes related to the Chohan family killings. However, before that, he was largely unknown outside of his community and the world of finance. His actions in the years leading up to his arrest were motivated by financial gain, which drove him to participate in a plot that ultimately led to his imprisonment.

Horncy was arrested in 2003 and later charged with serious crimes linked to the disappearance of the Chohan family. 

On February 15 and 16, 2003, in London, a tragic and brutal series of events unfolded involving the Chohan family. Amarjit Chohan, his wife Nancy, their two young sons, Ravinder and Devinder, and Nancy's mother, Charanjit Kaur, were all victims of a calculated crime.

Amarjit was lured to a meeting under false pretenses. He was abducted by Kenneth Regan and William Horncy, along with another accomplice, Peter Rees. Initially, Amarjit was held against his will, tortured, and forced to sign documents that would give control of his freight business, CIBA Freight, to Regan. The motive behind this was to take over the business for illegal activities, including drug trafficking.

In the days that followed, all members of the Chohan family were murdered. After killing them in their home, the bodies were transported to a remote farm in Devon, where they were buried. Subsequently, the gang became concerned about being discovered. On Easter Sunday, they exhumed the bodies and dumped them in the sea off Poole, Dorset. The actions taken were part of an effort to cover their tracks and hide the evidence of their crimes.

Over the course of several weeks, police investigations led to the discovery of Amarjit's body floating near Bournemouth Pier. Eventually, Nancy's and Charanjit's bodies were also recovered from the water. However, the bodies of the two young boys were never found.

Following extensive investigations, Kenneth Regan and William Horncy were arrested and charged with the murders. This led to a high-profile trial, where both men were convicted of the brutal killings, receiving whole-life sentences.