Law + Order; SVU * [CARELESS]

I just got finished watching an episode of SVU that absolutely made me sick. A young boy, about six years old, is killed. At first a priest is suspected of killing the boy during a "midnight exorcism". They find a mark from the priests ring on the boys chest that confirms this. They later go on to find out the boy was dead prior to the "exorcism". This leads detectives to believe the child's foster parents had something to do with it. Upon an investigation in the house where the child was staying, detectives find a pillow with bite marks on it as well as its pillow case, which had been found in the Tish, which match those of the victim. The fibers in the pillow match those found in the boys throat. This leads detective to believe his foster parents were behind the killing. The father is charged with the murder of his foster son. Later, we find out that is wasn't the father but his mother that smothered him. Apparently, they had been housing another child, a girl, and she had walked in on it and was then cut with a cheese grater by her foster mother. To cover it up, they sent her to a mental hospital and say she has gone crazy. It makes me sick to think that the social worker, who hadn't checked on the family in months just because she believe they were in good care, could have potentially prevented the death of this boy but had cases that were apparently more important.