It's not discrimination unless you make it about something other than the childs genuine safety, which is exactly what it sounds like. I absolutely agree that the police or cps must be contacted and if they are not, something will happen to that child. If you contact the authorities, you've done all you can do aside from pulling her out of the pool or the street (which you should do, too). If you do nothing, when something does happen, it will haunt you forever. I cannot imagine something like that on my conscience. Anonymous or not, you should act asap.