They planned to get his head.

The son of their chief, old One-Eyed Billy, had recruited on Lunga and died of dysentery.
That meant that a white man's head was owing to Suu--any white man, it didn't matter who so long as they got the head.

And Young was only a lad, and they made sure to get his easily.

They decoyed his whale-boat ashore with a promise of recruits, and killed all hands.

At the same instant, the Suu gang that was on board the _Minerva_ jumped Young.