"…Abby?"
Abby hung her head. "Yeah, you figured it out." She extracted a remote from her pocket and pushed a button. Instantly, the wailing ghost vanished. "How'd you know?"
"Well, my first clue was this keyboard key, which proved that someone had been using a computer to create the hologram of the Grey Lady."
"So? Lots of people have computers with missing keys."
"Right. Russ' laptop has seen better days as well. I also found this among the graves." She held up Everything You Ever Wanted to Know About Ghosts and Still Get to Sleep. "It's a research book about the Grey Lady legend at Camp Chase."
"But that could've been Kendra's, right?" Abby whined.
Velma nodded. "It could've been. So, I needed one more clue to pull everything together, and I found it when I was reading your paper." Abby rearranged her face into an appropriately puzzled look. "While it certainly isn't bad for a writer your age, it was a little choppy, with odd word choices. That's because you were trying to write around the missing letter T on your keyboard. And, since you were writing about Camp Chase, I deduced that the research book must have been yours as well."
Abby sighed. "Okay, okay, fine. You got me."
"The last piece of the puzzle, though, is why?" Fred piped in. "Why'd you do it?"
"Because," Abby blushed a few shades of red. "I'm…I'm your biggest fans. I wanted you to come solve a cool, spooky mystery like you do on TV. So I thought I'd make up my own mystery for you to solve. I'm sorry, you guys."
Fred chuckled. "It's okay, Abby. You did a really good job haunting the place."