another fact
Just to throw another log on the fire here. In case you didn't know, Child Protective Services are now regularly hit with multi-million dollar civil judgments for FAILING to take a child from suspicious circumstances. Here is the typical scenario: someone calls in the tip on the abusive (typically) boyfriend. CPS investigates and decides it doesn't have enough evidence and closes the case. The boyfriend kills the baby. Relatives of the baby sue CPS and win millions because hindsight is always 20/20.
With tort law the way it is, if I was in charge of CPS my standing orders would be "if in doubt, take custody." I would rather have to face an irate parent than a dead baby and a multi-million dollar judgment.