Imagine being in a dark room with ten other individuals and you can’t see shit. And suddenly one of the ten persons would start to hit you in the face really hard, only one of them.
Would you rather “micro manage” your way to find the scoundrel or would you rather burn the room with ALL ten of them, just to make sure?
Originally I just wanted to point out that you can dry out the pond when you start to strengthen the soon to be victims in a way; but before you’re able to do so you’ll have to find out who disappears and what they have in common so you can tackle the very problem of availability. If these occurences are happening in your own neighbourhood it should not be that hard to create an overall profile about the “typical” victim(s).
If the surroundings fail to “produce” more victims, the predator would also act more daring and uncareful, eventually reveailing its head in the process.