The first gold was found by Frederick Warner the expedition's surveyor on 6 August and further deposits were located on following days. However Hann thought they were not in commercial quantity; as a result James Venture Mulligan who in 1873 followed up Hann's report and announced richer deposits is credited with the discovery.
Obituary notice from The Queenslander, Brisbane, Saturday, 21 September 1889: "HANN--On the 5 April, William HANN, of Maryvale, North Queensland, accidentally drowned whilst bathing in the sea at Townsville, leaving a wife and two daughters to mourn the loss of an affectionate husband and loving father, aged 52."
Robert Logan Jack, Northmost Australia, George Robertson and Co., 1922
In addition to the obituary, the following article appeared in the Brisbane Courier 6 April 1889
A Townsville telegram dated 5 April states that William Hann of Maryvale Station, one of the oldest of the northern pioneers, committed suicide by drowning, in the bay in front of the Queen's Hotel during Thursday night.
This suggests that the drowning was not accidental and took place at night.