Lynch was born in Ireland around 1813 and was transported to New South Wales in 1832 for theft. He was assigned as a convict labourer in the Berrima district, in the southern highlands, and was tried for one murder in 1835 and acquitted.
Between 1835 and 1841 he killed ten people along the Great South Road, on the stretch between Berrima and Campbelltown. He fell in with carters travelling with bullock teams, walked beside them, and struck them from behind with a tomahawk; then he took the team and the load, sold them, and gave an account of having bought them. Four of the ten were one family, the Mulligans, killed in their house in 1841 so that he could take over the farm, the parents and two children. He burned or buried the bodies. He is recorded as the Berrima Axe Murderer, after the place he was tried.
Those named in the record are Thomas Smyth; William Frazer and his son; Edmund Ireland and a young Black boy recorded only as Billy; John and Bridget Mulligan and their children John and Mary; and Kernes Ladrigan.
He was arrested in 1841 after a man he had attacked survived, and the disappearances were connected. He was tried at Berrima, convicted, and hanged at Berrima jail on April 22, 1842. He dictated a confession to the priest who attended him, and it is the source of most of what is known about the individual killings.
He is the earliest case in this archive from Australia and one of the earliest anywhere for which a killer's own detailed account survives. The confession should be read as what it is, a document produced under sentence of death and mediated by the church, but the physical evidence and the surviving victim's testimony support its outline.