Human: Why did Johnstone's section sail to the mouth of what is now called the Mulgrave River? Assistant: 
Johnstone's section sailed to the mouth of what is now called the Mulgrave River and dispersed "a large mob of blacks" with gunfire. They then sailed further south to the Gladys Inlet (which is now known as the Johnstone River) where a large group of Aboriginals led by a very tall man decorated with pipeclay resisted the troopers' approach. Johnstone punished their "insolence" with gunfire and this leader was one of those killed