If they're illegal they've probably been here a while; guns, uniforms, apparently suspected the residence of having drugs, etc.
They got their s*** together. They might be born here. Might be gang bangers. But the rule of thumb is the more vicious the ethnic gang, the more likely they were not born here. They got that vicious 3rd world hell hole stuff hard wired into them.
This kind of thing is done ALL the time back home in Mexico. It has nothing to do with the WOD in the USA --- back home it's common for people to dress up like police and pull you over driving or walking down the street so you'll offer them a bribe. They can pretend to arrest you for jaywalking just to get you to pull out your wallet. And in Mexico the police do the same thing anyway --- it really makes no difference if it's the real police or pretend police.
This isn't America -- it's Mexico moved in.