Good thinking TIS!

The boy who drew the picture was the son of the original woman whose throat was slit. They thought the husband is the murderer, so the boy went into the system. A woman was taking care of him, that much was clear when Sarah went to check on him. His father now in on the death row, and will be soon executed, so they have started talking to him about his father. And he drew another picture with a bit of more detail so that helped Sarah to find the dumping site. Apparently this boy has been to that place one way or another.

And you are right on that excuse of a mother, and that prisoner!

She might as well have aborted her pregnancy, cause she got her daughter killed. Not shown, but that's what I guess.

That prisoner, (the father of that boy and husband of the original victim), one can't have any sympathy for him, just as you said one way or another he belongs there. He said there is no cowardice in holding a woman down and slitting her throat while she looks at you, or something to that effect. Add to that almost bashing that poor old chaplain's head to the bars and I wouldn't care less if they put him down.

So with that dumping site uncovered, a pimp and quite a strange pastor in the play, we see how it goes down.