Seated in his private office, tilted back in the big swivel chair, Mason propped his heels on the corner of his desk, held his interlocked fingers behind his head, and regarded Della Street with a lazy smile.

“Well,” he said, “this is one case where I have a free hand. Carr says I’m to do everything I can to uncover the truth. It makes no difference who gets hurt.”

“Even if it’s Karr himself?” she asked, studying him searchingly.

Mason nodded. His eyes, preoccupied now, were gazing through Della Street out past the walls of the office.

“You certainly did make that plain enough to him,” she said. “What were you trying to do, frighten him, or make him mad?”

“Neither. I just didn’t want any misunderstanding — and I wanted to know where I stood. Lieutenant Tragg is no one’s fool. One of the big things which keeps Karr from being rated as a likely suspect is the condition of his legs. Tragg isn’t going to take anyone’s word for that. He’s going to check up on it.”

“Ask permission to make an examination?”

“Oh, he won’t be that crude, not unless he gets something else to work on. After all, he’s not in a position to go around offending prominent taxpayers. He’ll go about it in a roundabout way, but he’ll be very thorough. Don’t worry about that.”

“You think he’ll be suspicious of Karr’s legs?”

“I would if I were in his place.”

She laughed. “Well, in a way, you are.”

Mason took his hands from behind his head, stretched out his left wrist, and consulted his strap watch. “Paul Drake’s late. He said he’d be in here ten minutes ago, and make a preliminary report. He... here he is now.”

Della Street was up out of her chair as soon as Paul Drake’s distinctive knock sounded on the door of the private office. She crossed over and opened it.

Paul Drake, head of the Drake Detective Agency, tall, thin, and with a look of perpetual, puzzled perplexity on his face, said, “Hello, gang.”

“Come in and sit,” Mason invited.

Della Street picked up her notebook, settled herself at a small secretarial table, and held her pen poised. Paul Drake slid into the big leather chair, squirmed around so that he was seated crosswise, took a notebook from his pocket, and said, “Well, it looks like one of those things.”

“How so?”

“The reason Lieutenant Tragg wasn’t particularly communicative,” Drake said, “is that he’s running around in circles. He doesn’t want to talk with anyone until he knows more what he has to talk about.”

“Let’s have it,” Mason said.

“I’m somewhat the same way myself, Perry. I’ve picked up as much as I can of what the police know and done a little snooping on my own.”

“What did you find out?”

“This man Hocksley is a mystery. I think Opal Sunley, that stenographer who comes in to transcribe the cylinders he dictates, knows more than she’s admitting. I think Mrs. Perlin, the housekeeper, knew a whole lot more than was good for her.”

“Just what did Hocksley do?”

“No one knows. Apparently he slept most of the day and spent the nights dictating. He’d use a dictating machine. The girl would come in and find anywhere from two to fifteen records waiting to be transcribed. Sometimes she’d have an easy day. Sometimes she’d have a hard day. Occasionally she wouldn’t be able to even finish the work that was laid out for her. She says it was virtually all correspondence, and that she didn’t pay much attention to the contents of the letters, simply typed them out, made sure there were no typographical errors, and left them for Hocksley to sign. She also made one carbon copy. She left that for Hocksley. She doesn’t know what he did with them. The point is there aren’t any files in the house, just a dictating machine, a cylinder-shaving machine, a transcribing machine, cylinders, a big stock of stationery, envelopes, postage stamps, a pair of scales, and that’s about all in the line of office equipment — except the safe.”

“What about the safe?”

“The safe is apparently the key to the whole situation,” Drake said.

“Tragg seemed very evasive about that safe when I talked with him,” Mason said.

“He would be. It’s a safe that cost money. It stands in the corner of Hocksley’s bedroom. It isn’t the sort of safe you’d pick up second hand somewhere and use to keep the ordinary bunch of office junk. It’s a safe that has individuality and distinction.”

“What was in the safe?” Mason asked.

“That’s another thing,” Drake said. “When the police got there, there were fifty dollars in cash, about a hundred dollars in postage stamps, and not another damned thing in the safe.”

“Was it locked?”

“It was locked. Opal Sunley gave Tragg the combination.”

“Then if a burglar had been working on it, he hadn’t done himself any good.”

“Perhaps not... He could have closed and locked it again.”

“Well, a hundred and fifty dollars is a hundred and fifty dollars,” Mason said.

“Uh huh. But the point is, the man who bought that safe didn’t buy it just for postage stamps and chicken-feed currency.”

“Okay, what about the shooting?”

“The shooting took place in that room where the safe is,” Drake said. “There’s some chance Hocksley surprised someone trying to get in the safe. It may have been the housekeeper.”

“How do they know the safe figured in it?” Mason asked.

“There’s blood on the floor in front of it, quite a little pool. That might indicate that it was a burglar who was shot. But Hocksley is missing, and the housekeeper is missing. There’s a trail of blood drops around through several rooms in the house, and more to the point, there’s blood in Hocksley’s automobile. So you pay your money and take your choice. Either a burglar killed Hocksley and the housekeeper and carted away the bodies, or Hocksley shot a burglar, then put him in the automobile and took him away. The blood in the automobile indicates that the person who had been shot was stretched out on the back seat of the car. That brings us to what seems to be the most logical explanation.”

“What’s that?”

“The housekeeper was the one who was trying to get in the safe. Hocksley shot her, wounded her, put her in the automobile, and took her away. Hocksley was a big, strong man who could have picked up the housekeeper and carried her out to the automobile. She was a slender woman in the fifties. She couldn’t have carried him. There were some burnt matches lying on the floor in the corridor of Hocksley’s flat — about half a dozen of them.”

“How much have you found out about Hocksley?” Mason asked.

“Not much. Hocksley’s a big, powerful man who walks with a decided limp. He’s very eccentric, and apparently interested primarily in being left absolutely alone.”

“That makes two of them,” Mason said.

“What?”

“Tenants in the same building who didn’t want to have anything to do with neighbors.”

“I gather it was a different situation with Hocksley, from what it was with Karr. Karr is a neurotic old crab. Hocksley was engaged in doing something he wanted kept an absolute secret. Hocksley worked at night, and slept during the daytime. The people who sold him the safe, the agent who rented him the house, the company that sold him his automobile all remember him more or less vaguely. But by putting the descriptions together, we have a pretty good picture of the man, about forty-eight or fifty with very broad shoulders and flaming red hair. His limp was quite noticeable — not the sort of limp you’d get from a stiffness in a leg, but the kind where one leg is shorter than the other.”

Mason asked, “Any connection between Hocksley or his housekeeper and anyone over in the Gentrie house?”

“No. The connection there is between Opal Sunley and Arthur Gentrie, Jr. That’s also something.”

“What?”

“Arthur Gentrie, the boy’s father, had been painting that night down in the cellar. I believe you’re the one who first noticed that someone who evidently didn’t know about that fresh paint had been groping for the garage door and had smeared paint on his fingertips. After you pointed this out to Tragg, he had the police look the automobiles over pretty carefully to see if they couldn’t find some trace of paint on the handles of the doors or on the steering wheels. They couldn’t find a thing, but over in Hocksley’s flat they found two fingerprints outlined in paint of exactly the same color as that used on the garage door.”

“Where were those paint fingerprints?” Mason asked.

Drake said, “On the desk telephone, and the desk telephone was on Hocksley’s desk, and Hocksley’s desk was in the room where the safe was located, and the telephone was right near the door of that room. Moreover, there’s a side door on the garage that Hocksley used to get in and out. That door opens into a little yard between the flat and the Gentrie house. It’s right near a side door leading to the Hocksley flat.”

“Were the fingerprints clear enough so the police could do anything with them?”

“Very clear. I think Tragg’s getting ready to do something there. He’s just waiting for the right time to strike.”

“Meaning he...” Mason broke off as the door from the outer office opened, and the girl who had charge of the switchboard timidly entered.

“I didn’t know whether to disturb you, Mr. Mason,” she said. “I told this woman you were in conference on an important matter, but she says that she wants to see you about the matter you’re talking over.”

“Who is she?” Mason asked.

“Her name is Gentrie, and there’s a young man with her, her son.”

Mason glanced at Drake.

Drake, consulting his notebook again, quoted: “He was in bed and asleep when the shot was fired. He came in, however, just about fifteen or twenty minutes before the shooting. He’d been out with Opal Sunley, the stenographer who handled Hocksley’s work.”

“You’re certain?” Mason asked.

“Uh huh.”

“I understood he was refusing to divulge the name of the woman...”

“Oh, sure,” Drake interrupted. “Some of that kid gallantry stuff, but Opal Sunley didn’t make any secret of it. She told the police right at the start. Young Gentrie didn’t rate the use of the family automobile, not for her, anyway. They were using streetcars. He took her to a movie, bought her a chocolate sundae afterwards, did a little mild necking in the park, and took her home about eleven-thirty. They said good night on the stairs for half an hour, and young Gentrie left about midnight. Evidently, he went right home and upstairs to bed.”

“He must have moved pretty fast if he left her home at midnight and was in bed at quarter past,” Mason said. “How far from Hocksley’s place does she live?”

“About twelve blocks. You can walk it in fifteen minutes if you’re young — and have just spent half an hour saying good night to your best girl.”

Mason said to the girl in the doorway, “Show them in. I have an idea something is weighing on that young man’s mind.”