On the 14th of January 1875, Constable Armstrong, Constable Barron, Constable Fahey and Aboriginal Police Assistant Jacky Brown, left Kojonup to arrest a man called Bobbinett on a warrant for the murder of a Police Boy called Jacky.  

They went to a sheep property near Etticup and were directed to a nearby camp in a bulrush swamp, as Bobbinett was there.

As the three officers approached, Bobbinettf shot and killed Constable Armstrong, he escaped in the confusion.  

Bobbinett was arrested on 20th February 1875 and sentenced to death on 9th April 1875, he was hanged at Perth Gaol.