How do you get koala on ty the Tasmanian tiger 2

First. Go talk to Julius, who is at Burrumadge HQ (The scientist koala). Then go to Dennis' house, the pink house, by the river, You will see 3 koalas standing there. Use your Infrarang/X-rang too see the spy. Beat it, then go talk to Julius again. Directly after that, talk to Ken, the guy standing by the sewers, then always use Infra/X-rang when you see a bunch of koalas too see a spy amongst them.