“But there must be dozens!” George objected. “How will I find them all?”

“Walk around the outside of the building. That’ll be fastest,” Nancy suggested. “Bess, you check out the front entrance. Find out who signed the guest register today and whether someone without an Emerson ID could have slipped in.”

“You got it, Nan.”

While her friends were busy with their assignments, Nancy borrowed a ladder and a knife from a janitor, cut down the effigy, and examined it. It was crudely sewn from a set of one-piece long underwear. Its head was part of a plain white pillowcase. Inside, it was stuffed with Styrofoam packing chips. No clues there, Nancy decided. Anyone could have assembled the materials.

She was studying the note pinned to the effigy’s chest when her friends returned.

“The exits can only be opened from the inside,” George reported. “Whoever did this was either let in or came in through the front entrance.”

“Good work. Bess?”

“The guard claims that security is extra tight because of those assaults the coach mentioned. Only students with Emerson ID cards can get in.”

“What about the guest register? Any names down for today?”

“Yes, three . . . Nancy Drew, George Fayne, and Bess Marvin. That’s it.”

“Terrific.” Nancy groaned. “That blows my first theory. I figured the joker might be someone connected with a rival team, but since it’s impossible to sneak in here that idea is out.”

“The joker could still have been let in through a side exit by someone else,” George reasoned.

Nancy shook her head. “I don’t think so. Practical jokers don’t usually work in pairs. My guess is that the culprit came in through the front entrance with the dummy hidden in a gym bag.”

“But, Nancy!” Bess was horrified. “If that’s true it means—”

“Yes. The practical joker is someone from Emerson College!”