What is the main problem in the book The Egypt Game?

I believe that there are two main conflicts going on in The Egypt Game. One conflict is an external conflict that affects the children as well as the greater community at large. That conflict is focused on the murderer that is somewhere present within the neighborhood. This conflict comes to a climax when April and Marshal are attacked by this person. The attack is thwarted by the Professor, who happens to be nearby and sees the attack. He calls for help, and the kids are able to get away. The murderer is caught soon after, and the neighborhood is returned to safety.
The other main conflict is an internal conflict for April. April has been forced to move into the neighborhood, and she isn't sure if she wants to stay there living with her grandmother. This conflict is also resolved by the end of the book. April has made several good friends, and she has discovered that she is happy with the place and the friendships that she has made.