John Lynch was born around 1812 in County Cavan, Ireland, the son of Owen Lynch. At the age of 19, he was convicted of “obtaining goods under false pretenses” and sentenced to life imprisonment. In October 1831, his father Owen was also convicted for having stolen goods in his possession and received a seven-year transportation sentence. Both were sent to New South Wales aboard the Dunvegan Castle, departing Dublin on 1 July 1832 and arriving in Sydney on 16 October. Upon arrival, Lynch was assigned as a ploughman to James Atkinson at ‘Oldbury Farm’ in the Bong Bong district near Berrima, while his father was assigned to a publican in Sydney. Owen Lynch died in February 1834 in the Sydney Gaol Hospital.

Lynch appears to have shared a violent and opportunistic streak from early on. In January 1836, a crime at Oldbury Farm—the murder of Thomas Smith—was loosely linked to a suspected gang of bushrangers. Lynch, along with another assigned convict, John Williamson, stood trial in August 1836 for Smith’s killing. The prosecution hinged on the testimony of another convict, Michael Hoy, but ultimately, due to lack of reliable evidence and poor witness credibility (including the intoxicated state of plantation overseer George Barton), both Lynch and Williamson were acquitted. Six years later, Lynch confessed to the murder, on the eve of his execution.

Following the Oldbury Farm trial, Lynch spent time in a convict gang, including being held in irons and working in the Newcastle stockade. In 1839, he claimed to have been stabbed by fellow convicts Thomas Barry, Thomas Bolson, and Charles Wilson, who were subsequently sentenced to death (their sentences later commuted). Lynch later admitted these wounds were self-inflicted to have the men punished in his place. He then absconded—possibly after applying for freedom he never received—and made his way back to Berrima by mid‑1841.

In the years after his 1836 acquittal for the killing at Oldbury Farm, John Lynch’s life fell deeper into the harsh grind of penal servitude. Described by the Berrima correspondent to the Sydney Herald as having “been a long time in irons in different parts,” he spent part of that time laboring in a Newcastle stockade gang before emerging—unannounced and dangerous—in Berrima in 1841.

One of the most telling episodes from his time in Newcastle was the infamous stabbing incident of 27 June 1839. Lynch reported that he was attacked in his hut by three inmates—Thomas Barry, Thomas Bolson, and Charles Wilson—who, evidently for retribution, bound his head in a blanket while one stabbed him in the chest. The three were tried in Sydney’s Supreme Court and sentenced to death, though their sentences were later commuted to transportation. Yet, in a chilling turn, Lynch confessed before his execution that he had staged the injuries himself to frame them—retribution disguised as victimhood. 

By mid‑1841, Lynch had slipped free and returned to the familiarity of Berrima. He first visited his old contact, John Mulligan, expecting a payoff. Denied what he felt was owed, Lynch moved on to the Oldbury Estate, stealing eight bullocks and driving them toward Sydney. Fate brought him to Razorback Range, where he encountered a carrier, Edmund Ireland, and his young Aboriginal helper. In his confession, Lynch said he “began to form the plan of destroying the men, and possessing himself of the dray and property.” The next morning, he killed them both with tomahawk blows, buried the bodies in the bush, and pressed on with the stolen dray and team.

Having disposed of the goods, Lynch headed back with the dray, crossing paths with William Fraser and his son, who were driving a horse team. They camped together at Bargo Brush. During the night, a police constable questioned them about the missing dray, triggering terror in Lynch. Alone under the dray, he trembled until the constable left. By dawn, driven by desperation and greed, he killed both Frasers with swift tomahawk strikes, burying them under a spade’s weight, and lingered at the site until dusk fell.

It was a short run from this atrocity to the next. Lynch headed to Mulligan’s farm at Wombat Brush. On 18 August 1841, under the guise of collecting owed debts, he ingratiated himself with the family, offering rum while calmly planning his betrayal. That night, he lured the 18‑year‑old son out to fetch wood, and killed him with an axe swing. When suspicion grew, he murdered both parents and then horrifically raped and killed the 13‑year‑old Mary. He piled the bodies, set them aflame—with a haunting remark that they “burned as if they were so many bags of fat”—then buried the remains and burned their clothes.

In a final act of deceit, Lynch placed a notice in the Sydney Gazette claiming that Mulligan’s wife had absconded, settling Mulligan’s debts in his name. He assumed the name John Dunleavy, brought in the unsuspecting Barnetts as laborers, and outwardly lived as the legitimate leaseholder. But neighbors pieced things together: bones were discovered, suspicions heightened, and investigations linked him to the multiple disappearances. By early 1842, authorities realized Lynch had confessed to a string of murders along the Berrima–Camden roads—and his fall from freedom was imminent.