Stephanie Bennett with the cover of her new e-book on the Gatton Murders “The Killer with 300 Names”.

Stephanie Bennett with the cover of her new e-book on the Gatton Murders “The Killer with 300 Names”. Derek Barry

THE infamous Gatton murders have lain unsolved for almost 120 years but Brisbane author Stephanie Bennett is convinced she has finally cracked the mystery.

Ms Bennett has painstaking put together all the pieces of the puzzle that led to the murder of three Murphy siblings on December 26, 1898, in a crime that shocked the nation.

She said she will reveal all in a new e-book about to be published called "The Man with 300 Names".

The book is the 86-year-old author's second on the topic having put together several theories but no conclusive proof in her original work in 2011 called "The Gatton Murders".

Ms Bennett said the inspiration for the second book came from a relative of the Murphys who told her the dead son Michael Murphy had dealings with itinerant worker Joe Quinn during the 1893 Shearer's Strike.

"So I had to learn all about the Shearer's Strike," she said.

Quinn was a serial offender who often concealed his identity to avoid detection by police, hence the "300 names".

"Quinn played a part in the murder with his brother Martin and another man who went by the name of Thomas Day," she said.

The murder took place between 10pm and 4am on December 26-27 1898 while Michael Murphy, 29 and his sisters Norah (Honora), 27, and Ellen (Theresa) 18 were returning home to Blackfellow's Creek from a dance that had been cancelled in Gatton eight kilometres away.

Michael had been shot and bludgeoned, Norah strangled and bludgeoned, and Ellen was bludgeoned twice.

The crime scene was destroyed by witnesses after the fact while the policeman leading the investigation Inspector Frederick Urquhart, head of the C.I. Branch in Brisbane, was known to be incompetent.

Ms Bennett said it was Inspector Urquhart that put her onto the Gatton Murders in the first place.

"I was reading about a murder at Carpentaria Downs he investigated in 1908 and the papers kept talking about his bungling in the Gatton Murders ten years earlier," she said.

"I had to learn more."

The new book will be available soon on Amazon and other e-book suppliers.