im with divine 1966 .. if it went on next to me since i really truthfully dont know whatever might be causing her to be screaming like that the next time it happened id be making a call to 911 & have the cops come & let them check the situation out to find out what actually is going on over there with her. you can hope what the mom told is the truth but bottom line is that she might be lying to you and its a worse set of circumstances that are really happening over there with that little girl....
perhaps explain when you call 911 that u prefer to remain "announamous" caller heard screams & called to report it so neighbors wont know it was u who had called the cops on them...