Ten minutes later a car with several officers reached the museum. One of them was Dr. Marcus, the police surgeon. He insisted upon examining each victim of the paralyzing searchlight.

He tested their responses and announced that the whole group was in good health. He asked them how they had felt during the immobile period. Professor t.i.tus and the girls said they had had no unusual sensations except being unable to move.

"May we please go upstairs and watch you open the door?" Nancy asked the locksmith detective.

"Certainly," he answered. "My name is Tim Rooney."

The whole group trooped up the stairway and watched as the detective tried one key after another. Finally he was able to unlock the door.

The girls wanted to rush up to the top floor but Dr. Marcus said, "No, not until we find it's safe."

A few minutes later he came down. "It's okay. You're in for a surprise," he remarked. "There's a fully equipped electrical and electronic lab up there."

"How amazing!" said Professor t.i.tus.

By this time Nancy had surmised as much. She led the way up the steps. What particularly drew her attention in the s.p.a.cious attic room were a series of pictures on the walls. They depicted gruesome scenes of battles, both between individuals and groups, and the slaughter of animals.

"How ghastly!" Bess exclaimed.

By now everyone was staring at the pictures of persons and animals about to have one eye gouged out with various kinds of hand weapons.

Bess covered her eyes with her hands just as Dr. Marcus said, "The man who owns these pictures is an unusual and dangerous killer type."

Nancy's heart jumped. "And he is holding Ned-" She could not finish the sentence.

CHAPTER XVIII.

Weird Heel Mark

"WHY, Nancy, you're white as a sheet!" Bess exclaimed. "What's the matter?"

"I was just thinking about what Crosson could do to Ned!"

George put an arm around her friend. "Please don't think the worst. I'm sure we'll capture that villain before he has a chance to do anything drastic." She went on to say that if Crosson were trying to get information out of Ned, he was not likely to kill him.

"But he might maim him," Nancy said with tears in her eyes. She buried her face in her hands and took a long, deep breath.

A few seconds later she raised her head and said, "You're absolutely right, George. I mustn't let my feelings overshadow my good sense."

She changed the subject by turning to Tim Rooney and asking if he would supply her with a key to the door leading to the attic.

He smiled and said, "You hope to trap the kidnapper right here in his own laboratory?"

Nancy nodded and Detective Rooney told her he would have a duplicate key made at once and bring it to her.

One of the other officers now asked Professor t.i.tus and the girls to leave the attic. "We want to search this place thoroughly for the glowing eye searchlight," he said. "Also, there may be other dangerous gadgets here which we should remove."

Nancy and the others went to the main lobby. George asked Nancy, "What's our next a.s.signment?"

The young detective replied, "I'd like to do some old-fashioned sleuthing. While Professor t.i.tus guards the museum, how about the rest of us taking flashlights and magnifying gla.s.ses outdoors to search? We're pretty sure that Crosson was here tonight. Perhaps he left footprints."

The professor agreed. The girls took sleuthing equipment from pockets and handbags, then went outside to examine the grounds.

A few minutes later Nancy's eyes were fastened on a trail of footprints which her flashlight and magnifying gla.s.s had revealed.

"Look!" she cried out.

The cousins came to her side. They saw the prints and presently found an identical one deep in a soft spot.

"The heel mark is a copy of Cyclops' glowing eye!" Nancy exclaimed as she pointed to it.

Clearly pictured was the ugly face of a Cyclops, with an eye in the center of his forehead.

George asked, "Do you think this is a mark Crosson uses just for himself or is it the insignia for his pals, too?"

Nancy admitted she did not know. "But I'm going to tell the police about this mark."

The girls went back into the museum. They were just in time to meet the police officers coming from the attic.

"We found nothing dangerous," Tim Rooney reported, "so it will be all right for you to go up there, Miss Drew. But be very careful just the same."

"I have something to show you," Nancy spoke up. "It's outdoors. Please follow me to the side of the house."

She led the policemen to the spot where she had discovered the heel print. The men stared at it, perplexed.

One said, "This is very strange. I'll call headquarters and see if they have any data on a similar mark."

They all returned to the museum lobby and he made the call. After listening for over five minutes, the officer said, "I'll pa.s.s along the information. This is most interesting."

He put down the phone and explained that a long time ago a band of wizards was reported to have lived in Europe.

"These men pretended to be magicians. Actually they were a gang of thieves. They mesmerized anyone who got in the way of their activities."

"Perhaps," Nancy commented, "the wizards were able to cause a temporary paralysis in people, and that's where Crosson got his idea for the paralyzing eye."

The officer looked directly at Nancy. "Do you think your friend Ned Nickerson had anything to do with inventing the glowing eye?"

"No," she answered quickly. "I suspect that Ned was working on something else which he was keeping a secret, but Crosson found out what it was and tried to steal the invention. But so far Ned has refused to give it to Crosson."

Before anyone could comment, they heard a loud knock on the front door. One of the officers went to answer it. The caller proved to be Tim Rooney. He laughed and said, "You all look as if you expected a monster. I'm just plain old Tim Rooney."

George spoke up. "It wouldn't have surprised us if a monster had arrived. Actually we thought the caller might be a wizard."

"Where did you get that idea?" Mr. Rooney laughed.

Nancy told him what had been discovered during his absence. He was intrigued by the story of the ancient gang of wizards.