Mystery of the Green Goblin - Shadow Boy Mystery Series, #2

Huby as in the red ruby, the strange boy who sees the future, mysteriously materializes out of nowhere to return in this exciting sequel to The Mystery Under Third Base. It's Halloween and Alex Cooper, age 11, is wearing a green goblin costume. On mischief night, Alex's hated math teacher falls down the stairs and suffers a fatal head injury when his mailbox blows up. A green goblin was seen near the teacher's house that night, and by the next day everyone believes that Alex Cooper murdered his teacher, including the police.
Join Huby, Alex, and his schoolmates as they set out to prove that Alex did not commit the crime. Is there really a nasty green goblin in town, and what part do Alex's sometimes friends, Trash and Mungo, the town's bad boys, have to do with it?