John Dunn was associated with the bushrangers Ben Hall and John Gilbert. Dunn joined the Hall gang in October 1864, he was a welcomed new member because the police had caught the following bushrangers Dunleavy and Mount in late 1864. During the robbery of a mail coach Gilbert sot and killed sergeant Parry. On 26 January 1865, Hall, Gilbert and Dunn were at Collector, near Lake George. Dunn twice shot and killed the local police officer, Constable Samuel Nelson, The sole police man in the township and the father of eight. While Hall and Gilbert were holding up the hotel, Dunn also shot at Nelson's son but missed.