Megan Atwood 
Mayhem on Mohawk Avenue [PDF ebook] 

A dark, shiny poster was spread across the board, crowding out school lunch menus and events calendars: NEED TO BANISH A GHOST? CALL THE PARANORMALATOR. I SEEK KNOWLEDGE AND FIND THE SOURCE. Jackson and Jinx looked at each other. Jinx’s mouth hung wide open. Everything about the poster ripped off the Paranormalists. When a new kid in town tries to get in on Jinx and Jackson’s paranormal investigation business, Jinx is furious. But Jinx’s quest to shut down her competition will lead them down a dangerous path . . .