What's the Name of That Book??? discussion

This is a book I remember reading when I was young, probably under the age of 13. I read it in the 90s but I have no idea when it might have been published.

The story takes place in America, in a city or suburb with a large homeless population. The main character and his best friend are both young kids, probably around 10-13.

A murder of a young man occurs, and no one knows who the victim was because he was homeless, but police are trying to get information. The main characters either end up volunteering at a homeless shelter or otherwise end up there talking to a man who has a different name but insists on calling himself Abraham. He keeps making hints to the fact that he killed Isaac or was told to kill Isaac.

Iirc the kids don't understand the reference at first, or one does and the other doesn't. I think they believe "Abraham" is innocent, and that he just believes he killed Isaac but he didn't really. They spend most of the book trying to figure out how to prove his innocence, I think. I don't remember much more but I think there's a scene where the main character's parents tell him not to talk to Abraham anymore and the main character defies them.

A few guesses:
- At the Sound of the Beep by Marilyn Sachs?
- Dew Drop Dead by James Howe?

Squash, can you tell us more about the two boys (age 10-13) - e.g., homeless, runaways, living with their families; how do they learn about the murder?

Is there a serial killer?

Kris wrote: "A few guesses:
- At the Sound of the Beep by Marilyn Sachs?
- Dew Drop Dead by James Howe?

Squash, can you tell us more about the two boy..."

They live with their families, and I think they're middle class or at least well-off. If I recall correctly, they learn about the murder because they see the body being fished out of a river. I don't remember the conclusion of the story, so I'm not sure whether it was a serial killer or something else. I don't think the main character himself is religious; I think I remember the two kids going to the library and looking up the story of Abraham and Isaac.

I do remember a scene where they go and visit Abraham at a shelter, and they talk to him while he's sitting on a bed, because they're trying to figure out what happened to clear his name. I think he just says the same bible verse over and over rather than answering any of their questions.

Squash, are you still looking for this or did you find it?