Follow the same path you took when you came to rescue Roland. Quick travel to the Bloodshot Stronghold after you’ve picked up the pizza. Yes, strange as it sounds these creatures seem to be obsessed with pizza and you can find a fresh one sitting at Moxxi’s bar.
But, before you head there you’re going to need to draw them out of hiding with some pizza. These mutated bandits take to the sewers pretty quickly and so far there’s only place they could be: the Bloodshot Stronghold. Tannis needs you to take care of some nasty, mutated Hyperion experiments that have escaped the Hyperion reserve.