Frank also thought they should go out once more to the Mead estate and dive under the boathouse door to see if Chet's stolen dory had been taken there.

"It sounds like a full morning," said Mrs. Hardy, "but please lay everything aside and try to find Martha Johnson."

"We certainly will, Mother."

Suddenly from the Hardy kitchen came sounds of a news broadcast. The laundress, who had arrived for work, was eating her breakfast and had turned on the kitchen radio. It was very loud, and the words were plainly audible in the dining room.

"-A local item of great interest," stated the announcer, "is about another baffling robbery."

Frank and Joe sat up straight in their chairs. They listened attentively as the newscaster went on: 130 "Thieves broke into the Cornish Museum last night. Many small valuable items were stolen. The police are completely baffled. No one was seen to enter the place, and a detective inside was found injured and taken to the hospital."

Frank and Joe looked at each other. Their hearts stood still.

Was the victim their father?

CHAPTER XVI.

Fingerprints.

the four at the breakfast table were shocked by the thought that Mr. Hardy might be lying in a hospital, the victim of some clever thief. The boys' mother tapped nervously on the table.

For once Aunt Gertrude seemed tongue-tied. Joe was the first to find his voice.

"Let's call up every hospital till we locate Dad," he cried, starting for the telephone.

"Wait a minute!" Frank advised, catching hold of his brother's arm. "I don't believe it was Dad after all."

He explained that the victim certainly was known; probably he was a member of the police department of the town of Cornish. Had the man been Mr. Hardy, surely his family would have been notified by this time. Aunt Gertrude, now over her scare, sniffed: "Well, knowing my brother as I do, I'd say the whole thing is a hoax."

131.

132 "What do you mean?" Mrs. Hardy asked.

"I mean that I believe this was a clever idea of Fenton's. If he pretends to be injured, and if those crooks think he's in a hospital, they may come out into the open."

"And be caught!" yelled Joe. "I'll bet you're right, Aunt Gertrude."

Miss Hardy looked pleased. "So I guess we needn't worry any more about Fenton. You boys can get started looking for Martha."

For a few seconds Frank and Joe had completely forgotten the work they had mapped out for themselves. Now, being reminded that they ought to get busy, they left the house.

Their first stop was Police Headquarters to see Chief Collig.

"Say, you boys weren't giving us the run-around on that Packer Street story, were you?"

the officer asked suspiciously.

"Now, Chief," grinned Joe, "you know we could never do that to you. You'd catch on right away."

Collig smiled. He was in a good mood.

"You found out yet how to get into that lockless Mead mansion?" he teased.

"Yes, we have, Chief," Joe replied. "We waved our arms in front of the door and said 'Bay-Bay-Bayport, C-C-Collig.' And it opened!"

The officer laughed until he was red in the face. Then in answer to a question from Frank, he told the boy his men had orders to watch the house at 47 Packer Street constantly.

133 "Not a person has gone in or out of it," the officer reported. "Are you sure that was the address of the house in which you were attacked?"

"I'm positive," Frank replied. "Chief Collig, would you mind if we go over there now and look around inside?"

The boy did not state his reason, but it had occurred to him that possibly Lenny Stryker and the nurse, Martha Johnson, were imprisoned near by. Frank wanted to hunt for a secret panel which might lead underground to an adjoining building.

"It's all right with me, boys." Collig gave his permission. "So far as I know, the place is vacant and has been for some time."

"Where can we get a key?" Joe asked quickly.

The Chief, glad to show his efficiency, said he already had obtained one from the real-estate agent who had charge of the place.

Collig took the key from a drawer, and handed it to the boy. He spoke into his office telephone, ordering Patrolman Riley to come from the back room and accompany the Hardys. Frank and Joe hurried toward 47 Packer Street. The plump patrolman tried in vain to keep up with them.

"Take it easy, fellows," he pleaded, red-faced and puffing. "I just had my breakfast. One shouldn't run on a full stomach."

"Could you run on an empty one?" Joe flung back over his shoulder.

Riley was not sure what the boy meant. Now 134 that he thought about it, one couldn't run in that position at all. To the patrolman, his stomach was a very important matter indeed. He loved to eat. When he talked, Riley had a habit of patting himself near his waistline, which showed definite signs of his big appet.i.te.

As a result of his size, he arrived at 47 Packer Street a good five minutes after the Hardys had reached the house. The boys were already inside the deserted house, tapping its walls for a possible secret panel.

"What in thunder are you fellows doing?" Riley asked them.

"Hunting for ghosts," Joe explained.

He and Frank had promised Mrs. Stryker they would not divulge her secret. Even though the police might eventually have to know the story, Riley was not the member of the force to be told about it. The patrolman did not offer to help the boys. After a while he guffawed at their efforts.

"Ghosts, eh? You two make me laugh. This ain't the kind of house where a ghost would live."

"I guess you're right," Frank conceded at last. He and his brother had found nothing to indicate a secret panel. "But there's one thing sure. Some live ghosts have been here, and pretty recently, too."

"What do you mean?" Riley demanded.

Frank pointed to a number of footprints plainly visible on the dusty floors.

"So what?" Riley asked. "There's nothin' special 135 about them. The police have been here." He squinted at one particularly heavy mark in the room where the boys had been locked in. "I could swear that one belongs to Patrolman Crossley."

"What about these finger marks?" Frank pointed to a window sill. "Are they Crossley's?"

The patrolman grunted. "How should I know?" he said. "What difference does it make anyhow?"

Frank did not explain. Turning to Joe he said, "How about you going home to get our kit?"

Riley was completely confused. He saw no necessity for more investigation. But he had been outsmarted so many times, due to the acuteness of the Hardy boys, that he did not argue further.

It was Frank's idea that the fingerprints and footprints might belong to friends of the thief who had taken Chet's boat. Convinced that there was some connection between him and the museum robbers, the boy decided to take photographs of the marks. It seemed all the more important now, since the folder containing the fingerprint records had been stolen from Mr. Hardy's files.

Joe raced home and grabbed up his kit. When he returned to 47 Packer Street, Riley gasped.

"I didn't know you fellows owned anything like that," he said. "And how'd you learn to work it?" The patrolman was envious. He had studied fingerprinting at Headquarters but had failed to pa.s.s the test.

"Dad taught us," said Joe, taking out the special 136 camera and holding it over the white window sill.

He clicked on the lights in the camera and squinted into the focusing panel. The fingerprints showed up plainly.

"Won't need any powder on these, Frank," he said.

"Good. I found some marks on this wall but they're not very plain. Think I'll powder "em."

While Joe busied himself taking five-, ten-, and fifteen-second time exposures of the fingerprints on the window sill, Frank opened a bottle of gray-colored powder and poured a little of it on a sheet of paper. Next he picked up a small camel's-hair brush by the handle and twirled it back and forth between his palms to make it fluffy. Then, after dipping the tip of the brush into the powder, the boy pa.s.sed it lightly over the indistinct fingerprints on the wall.

"Ready for the picture, Joe," he announced.

His brother came across the room. Patrolman Riley came also, saying he wanted to look into the camera. Joe let him, but the clumsy man snapped the finger release by mistake and wasted a film.

"Oh, I'm awful sorry, Joe." Riley was fl.u.s.tered.

The Hardy boy said nothing. He took the camera, focused it, and took several pictures of the fingerprints on the wall.

"Okay," he said. Before putting the camera back into the kit, Joe took snaps of the various footprints on the floor of the room, then he said, "Guess we'd better go home now, Frank, and develop these pic137 tures. I certainly hope they turn out all right."

Riley still was amazed. Shaking his head the officer left the boys, who hurried home.

They had just finished developing the pictures in the cellar laboratory, when their father walked in.

"Dad!" Joe cried, rushing up to him. "You're all right!"

"Of course I'm all right," Mr. Hardy grinned. "Wasn't I supposed to be?"

His sons looked at their father intently. They were sure there was a trace of a smile around the corners of his mouth.

"You know you aren't supposed to be all right," said Frank. "I'll bet you came home in a disguise."

The detective grinned. His son had guessed the truth! Also his sister. A dummy figure had been put on guard inside the Cornish Museum, and judging from the distorted appearance of its plastic face, the thief who had entered the museum had made a good job of knocking it out!

"But I'm sorry to say that, though the Cornish police were on guard outside, they did not catch the intruder." Mr. Hardy sighed.

"Where were you, Dad?" Joe asked.

"Over in Harlington. Nothing happened at the museum there."

"But the crooks think you're in the hospital?"

Mr. Hardy nodded. Then he inquired what the boys were doing. Upon hearing that his fingerprint records of the museum thieves had been taken from 138 his filing cabinet, the detective was very upset. It was a big loss.

"We hope the fingerprints we have just photographed will take their place," Frank told his father, after he had explained their latest work.

Mr. Hardy agreed there was good logic to the idea. He told his sons he had obtained photographs of the fingerprints on the book the boys had discovered in the country garage.

Taking them from his kit, he compared the swirls and ridges with those in the photographs Frank and Joe had just developed.

"One set in each is identical!" he exclaimed. "Boys, you have done a good job!"

It now was definitely established that the fellow who had sold Chet the battered dory, and then stolen it, was at least acquainted with the museum thieves and probably was one of them. Frank asked his father why the police who had been guarding the Cornish Museum had been unable to capture the intruder.

"Because he is a very clever fellow," the detective replied. "I wish he would put his brains to good use, instead of bad."

"Have you figured out how he manages to open doors without leaving any trace?"

Mr. Hardy did have a theory. Probably the thief had some kind of invention which, when inserted in any keyhole, would move the tumblers of the lock electronically.

"Meaning a short-wave key?" Joe asked.

139 "You might call it that, son," the detective laughed. "In any case, it seems to me the only plausible answer to these mysterious entries is something of the sort."

"It's sure a clever idea," said Frank. "But, Dad, you haven't told us yet how the thief managed to get past the police."

The detective explained that a man had handed a letter from the Chief of Police at Cornish to the guard at the main door of the museum. The note had said the guard was to leave at once for home, and the newcomer was to take his place."

"And the newcomer had forged the note," guessed Joe. "He really was the thief?"

"Correct, son," said Mr. Hardy. "Between the time that the guard was dismissed and the hoax was discovered, the thief had entered the museum, taken many valuable pieces, and vanished."

"How do you know he didn't use a key?" Frank inquired.

The detective said a special new lock had been put on the front door of the museum that very afternoon. It was an intricate one, as nearly burglarproof as locks are made today.

"The lock was examined carefully after the robbery, and it showed no sign of having been tampered with," the detective went on. "That's why I feel sure he used some clever, new device."

Frank and Joe were fascinated by the idea, and hoped to learn very soon what this invention was.

140 They asked their father if he had any special job for them, and learning he did not need them, decided to go on with their own sleuthing. They left the house a few minutes later by bus, and returned to the section which they had investigated slightly the night before last-one of the spots which was ten minutes from "singing" traffic light number two.

By daylight the place proved to be a new housing development. Only a few of the homes were occupied, while others were in various stages of building.