They were all convicted murderers. Some claimed to have killed in self-defence or a fit of passion.

Mitigating circumstances were not recognised under law at that time. The penalty for murder was death.

Thomas Newman was hanged on May 29, 1877 after being found guilty of the rape, mutilation and strangulation of Mary Ann McGregor at Coonabarabran.

The alarm was raised when the 12-year-old did not return from a visit to a neighbouring farm.

Mary Ann's brother David rode out to look for her and found Newman grazing sheep.

The 30-year-old shepherd is alleged to have said "She is lying on the ridge - I do not think she is dead".

Police searched Newman's sleeping quarters and found items belonging to the dead girl - a chemise, pieces of blue and pink ribbon, earrings, some beads and a piece of metal from a brooch.

Newman's shirt was torn, he had blood on his trousers and a button from his coat was found near Mary Ann's body.

The married father of two is reported to have confessed after he was found guilty of murder.

He is said to have feared the consequences of rape and planned to burn the body "but she was missed too soon".

The Australian Town and Country Journal of June 2, 1877 reported Newman ate a good breakfast before the execution and remained "cool and calm" throughout "the dreadful preliminaries.

"He slept from 12 o'clock till half-past four, when on waking he prayed very fervently. After being pinioned he stepped very firmly up the flight of stairs - and never once faltered," the newspaper said.

Newman's last words to Reverend Graham were "Goodbye, tell the congregation I die in peace with God".

An Aboriginal man named Albert was the next prisoner executed at Dubbo.

The 22-year-old stockman was hanged on May 26, 1880 for the shooting deaths of Nugle Jack and Sally at an Aboriginal camp at Baradine.

Official records indicate only one shot was fired which passed through both of them.

The next prisoner executed at Dubbo was Lars Peter Hansen. He went to the gallows on June 2, 1891.

The 30-year-old farmer and gardener denied killing Charles Dunckner on the Peak Hill road. (Gaol records indictate the deceased may also have been known as Duncker or Drucker).

Newspaper reports said the victim had been "fearfully mutilated apparently with a tomahawk". The body had been partially burnt.

Hansen and Dunckner were said to have been friends who were seen travelling together between Sydney and Peak Hill.

In the days after the murder Hansen had gone to Sydney where he tried to sell some of the dead man's possessions.

At the time of his arrest in Wollongong, Hansen had Duckner's hat and revolver.

Five months later Harold Dutton Mallallieu was hanged for the murder of Jerome Carey (also known as Jack Wilson and John Wilson).

The deceased's bones had been found on a heap of burning ashes at Moonagee, near Nyngan, on March 22, 1891.

Thomas Moore was the oldest prisoner to be sent to the gallows at Dubbo.

The 65-year-old former hangman, labourer and hawker had been convicted of the bashing murder of Eddie (Joseph) Smith at Brennan's Bend on the Darling River at Bourke in November 1896.

At the time of his arrest Moore had some of Smith's property in his possession, including a cheque the dead man had received for fish he had sold.

Moore also had items belonging to murder victim Tom Andersen. He was a suspect in two other killings.

Moore was a devout Catholic and kissed a crucifix when he walked to the scaffold on June 24, 1897, calmly mounted the 13 steps and stood unassisted while hangman Robert Rice Howard adjusted the rope.

Chinese born Wong Ming was executed at Dubbo on December 13, 1898. He was found guilty of murdering fellow countryman Joe Mow Jom and the stabbing of Alice Spong.

But it was the hanging of Jacky Underwood on January 14, 1901, which was reported by newspapers across Australia.

Underwood was sentenced to death for his involvement in the murders of Percy, Hilda, Grace and Sarah Ann Mawbey and Helen Kerz at Breelong, near Gilgandra, on July 20, 1900.

Brothers Jimmy and Joe Governor were said to have led the attack, later known as the Breelong Massacre.

A young member of the Mawbey family survived and raised the alarm.

Underwood, also known as Charlie Brown, was quickly caught.

The Governor brothers went on a 14-week, 2000 mile (3219km) rampage terrorising a wide area of northern and central NSW.

They killed Alexander McKay near Ulan on July 23, Elizabeth O'Brien and her baby son at Poggie, near Merriwa, on July 24, and Keiran Fitzpatrick near Wollar, on July 26.

After several close escapes Jimmy Governor was shot in the mouth on October 13. In a weakened condition, he was captured on October 27. Joe Governor was shot dead four days later.

Underwood was charged with "feloniously murdering Percy Mawbey, a child". He denied the offence.

Jimmy Governor was executed at Darlinghurst gaol on January 18.

Ah Check was the last man to hang at Dubbo gaol.

The 66-year-old labourer was accused of murdering William Tregaskis at Peak Hill on February 17, 1904.

Police said the victim was shot at close range and his head was almost severed from his body with an axe.

Police were told Ah Check had been working in the bush ringbarking trees for Tregaskis. Witnesses said the two men had argued.

Ah Check testified he had worked for weeks without payment.

Ah Check pleaded not guilty and claimed Tregaskis was shot in self-defence when the property owner lost his temper and lashed out with an axe he was carrying.

During his trial Ah Check said "Tregaskis he chop 'em me, me shoot him - that one black heart. Me killee him, he very bad."

The Australian Town and Country Journal published an account of the June 28, 1904 execution.

"Shortly after nine o'clock the procession headed by Reverend E. H. Lea (the rector of Holy Trinity Church Dubbo) and the Reverend Soo Hoo Ten passed from the condemned cell to - the gallows screened by calico on all sides," the newspaper said.

"Only the mayor of the town, three newspaper reporters and gaol officials were present."

Thomas Newman, Albert and Harold Dutton Mallalieu were buried in unmarked graves in the Dubbo gaol grounds.

The unusual practice has intrigued state and local officials who don't know why the trio were not interred alongside other gaol inmates in the Myall Street graveyard now known as Old Dubbo Cemetery.

Mary Ann Wilson was also buried at the gaol. She was not a prisoner and died in peculiar circumstances in January 1885. She was found in an exhausted state in bushland near Nyngan. Her husband was lying dead nearby. An eight-year-old child was also discovered by police. The whereabouts of the couple's three other children was not known.

Mary Ann and the child were brought to Dubbo by rail and taken to the gaol because the hospital was full. A medical examination determined the woman was suffering severely from dropsy (an old term for the swelling of soft tissues due to the accumulation of excess fluid) and heart disease.

The inquest verdict found death resulted from natural causes "accelerated by drink and exposure".