Bob arrived at the library later than he’d hoped. He quickly decided that the telephone directories on the library shelves would be no help. There were columns and columns of listings for Navarro in the Los Angeles telephone book but not a single one for Sogamoso.

Bob sighed, spread the print-out of the computer message on the table in front of him, and scowled at it.

MARILYN — START SOGAMOSO, read the message. GO TO OLD WOMAN. AT SUNSET ON MIDSUMMER DAY HER SHADOW TOUCHES THE TEARS OF THE GODS. ALL FOR YOU, BUT WATCH OUT FOR NAVARRO. IS HE LEGAL? CHECK INS.

What now, Bob wondered. The names of Navarro and Sogamoso were the only real clues the message contained. The initials INS probably referred to the Immigration and Naturalization Service, and Navarro might be an illegal alien. It wasn’t very helpful to know that. Unless perhaps Pilcher meant that his daughter was to turn Navarro in to the INS if the man appeared. Meanwhile, the message was so obscure that it was maddening.

And why would Jeremy Pilcher leave a cryptic note in the memory of his computer? Marilyn did not seem to be a computer whiz. Pilcher couldn’t have been sure she would ever see the message.

But perhaps Pilcher hadn’t had time to make a more sensible plan. He might have suddenly become aware that he was threatened. If the person who threatened him knew nothing about computers, the message could be hidden in Pilcher’s machine safely enough. But if Marilyn didn’t understand a word of it, it would do her no good either.

Bob worked part-time in this library, and he knew its layout well. He went over to the reference shelves where there were directories of business firms. Jeremy Pilcher was a businessman, so there was a good chance that Sogamoso had something to do with a business. Bob looked for Sogamoso in Standard & Poor’s, a big book that listed American companies. He went through the index to The Wall Street Journal and to Forbes magazine. He found no mention of Sogamoso. The name did not appear in any edition of Who’s Who.

Well then, thought Bob, Sogamoso was not a prominent person. It was not a business. Sogamoso must be something else entirely. The idea sent him to a Spanish-English dictionary. When he did not find the word there, he went doggedly on to the big atlas on the bottom shelf in the reference section. And there at last he found it — in the index at the back.

Sogamoso was a town in Colombia. “The library will close in ten minutes!” warned a voice on the public-address system. Frantically Bob turned to the page number given in the index. It showed a map of the northwest corner of South America. Colombia was there, its borders outlined in purple, the lofty Andes Mountains depicted as white ridges running slantwise on the page.

Bob squinted. Sogamoso. The index had given the population of the place as a little over 49,000. It wasn’t a large city.

It turned out to be a speck in the mountains northeast of Bogota. Why on earth would Pilcher want Marilyn to go to this remote place and find an old woman? And would any old woman do? Or must it be one particular old woman?

A brief description of Colombia appeared next to the map. “Colombia is almost unsettled,” Bob read, “except in the narrow region between the coast and the western foothills of the Andes. In the wet lowlands near the coast, sugar cane and cacao are grown. In the altitudes from 3,000 to 6,500 feet Colombians grow one of the largest coffee crops in the world. Wheat and barley are raised in the mountain basins, and sheep are herded in the alpine meadows. Textiles are manufactured in the Antioquia Valley. A steel industry exists in the iron and coal area near Sogamoso, and there are also gold and emerald mines in the mountains. Most Colombians depend on income from coffee.”

The overhead lights flicked. “The library will close in five minutes,” said the loudspeaker.

Bob shoved the atlas aside and hurried to the shelves where the encyclopedias were lined up. The article on Colombia in the Americana was pages long. The Britannica also devoted a fair amount of space to it. There wasn’t enough time to read it all, and he couldn’t take the reference books out of he library.

The overhead lights flicked again. Bob raced to the shelves where books on South America were kept and scooped off two volumes. One was titled Colombia, Land of Contrasts. The other was Colombia, from New Granada to Bolivar.

Bob snatched up his print-out and hurried to the check-out desk. A moment later he was taking his bike from the rack near the library entrance. He wished he had had time to browse through the books on Colombia. He probably hadn’t chosen the most useful ones. Or perhaps he had. The books he had snatched up just might contain the clues that the Three Investigators needed to solve the mystery of the cranky collector.

Eager to begin reading, Bob pedaled off toward his home.

It was almost ten o’clock when Pete Crenshaw heard the footsteps. He and Marilyn Pilcher were in the living room of the Pilcher house. They had eaten fried chicken from the Cheerful Chicken carry-out place on the highway, and they had a fire going in the fireplace. The room was almost too warm, but the fire cast a nice glow and drove the shadows back to the corners.

Then the pacing began.

They were playing Trivial Pursuit and Marilyn was winning when the first steps came from above. Pete knew instantly that someone was moving about in the attic. In the silent house, the sound penetrated all the way to the first floor.

Pete’s heart sank. He did not want to go upstairs. He disliked the Pilcher house. He disliked everything about it. It was cold and damp. It needed cleaning and airing out, and it had the sort of attic nobody needed — an attic where some unseen being had walked last night. True, Pete had not been on watch last night. He had not heard the restless pacing, but Bob and Jupe had told him about it.

And now it was starting again.

Marilyn looked up. “Did you hear it?” she said. She was whispering.

Pete wanted to say no, but he couldn’t. He looked away from Marilyn and said nothing.

“Did you lock the back door?” Marilyn asked.

“I–I thought you did,” he countered.

She stood up, looking toward the kitchen. “Someone could have come in.”

“We’d have heard them,” said Pete. “We’d have known it if the door opened.”

But he went to the kitchen. The door was locked. The dead bolt was on. No one had come in.

Or had an intruder come in, then turned the dead bolt from the inside? Marilyn came into the kitchen and stared at the door. She frowned, then went back out. Pete followed her to the hall, where she stared up the stairs. “Listen!” she said.

The footsteps were louder now. They made a hollow sound on the bare boards of the attic floor.

“Blast!” Marilyn went to the phone, lifted the receiver, and dialed 911. “I want to report a prowler,” she said.

But was it a prowler? Pete wondered. Jupe said that last night no one came up the stairs and no one went down. Yet someone had walked in the attic, and walked and walked. “Creepy!” said Pete out loud. Marilyn ignored him. She was giving the address to the dispatcher on the other end of the line.

Pete started up the stairs. He was trembling and his throat was so dry that he couldn’t swallow, but he went up anyway, step by step.

The pacing in the attic continued. A ghost? Or something more dangerous than a ghost?

Marilyn hung up the phone and followed Pete. She was no longer the arrogant rich girl. She was afraid, and she kept close to the big, athletic boy.

“When I was little,” she said, “we had a cook who got her jollies scaring kids. She told me this house was haunted.”