On his release from prison in July 1891, Deeming headed to the Liverpool area, settling into a hotel in the village of Rainhill, Merseyside.
While in Rainhill, Deeming began to court Emily Lydia Mather, the daughter of a widowed local shopkeeper, Mrs Dove Mather. Emily and Deeming (as Albert Williams) married on 22 September 1891.
In November 1891, Deeming (still using the name Williams) took Emily to Australia in the German steamship "Kaiser Wilhelm II." They arrived in Melbourne on 15 December 1891. Deeming rented a house in Andrew Street Windsor, a suburb of Melbourne. On 24 December or early on 25 December 1891, he murdered Emily and buried her under the hearthstone of one of the bedrooms, covering the body with cement. He had paid a month's rent in advance, giving the name Mr. Drewn, but almost immediately left the property. The owner, nearby butcher John Stamford, had been happy to rent to the man, because of his air of respectability, and at first had not even known the man’s name.
On 3 March 1892 a prospective tenant of the Windsor house complained of "a disagreeable smell" in the second bedroom. The owner and estate agent later raised the hearthstone to investigate whereupon the smell became so overpowering "they found themselves barely able to breathe". The police were called and the body of Emily Mather found. A postmortem conducted on 4 March found that although her skull had been fractured by several blows, the most likely cause of death was that her throat had been cut.