Frank stopped at the bottom of the stairs and saw Mrs. Zimmerman, the landlady, sitting in the parlor, weeping softly into her handkerchief.

“Excuse me, ma’am,” he said.

She looked up, her red-rimmed eyes brimming. “Oh, Mr. Malloy, I’m so glad you was the one who found him. That sweet boy, I don’t know if I could’ve stood it or not. I should’ve knowed something was wrong, though. I should’ve gone up to check when he didn’t come down to breakfast. Maybe if I had-”

“The coroner said he died real quick,” Malloy said by way of comfort. No use in the woman torturing herself. “There was nothing you could’ve done.”

“I wish he’d come and talked to me if he was feeling poorly. Maybe I could’ve said something to stop him.”

“I wish he’d come to me, too,” Frank said, “but he didn’t. Sometimes, you just can’t help, Mrs. Zimmerman. If someone is determined to kill themselves, they’ll do it. There is something I’d like to ask you, though.”

“Oh,” she said, as if remembering. “You’ll be wanting a refund on the rent you paid for him. There’s three days left, I think. I’ll get-”

“No, it’s not that,” Frank said. “You keep the money, for your trouble. It’s just… I packed his things to send them home, but I don’t know his address. I was wondering if you had any idea-”

“Oh, my, yes! I’d almost forgot. He give me a letter to mail to his dear mother just yesterday. Wait right here, I’ll fetch it.”

Calvin had written to his mother yesterday. He’d made his decision quickly, then. He wouldn’t have bothered with a letter if he’d known he was going to be leaving a suicide note so soon. What could have caused him to decide to do something like that when he seemed to be getting away with the crime? Certainly, he had every reason to believe he’d fooled Frank, at least.

Before Frank could make any sense of it, Mrs. Zimmerman was back. She held out an envelope to him with one hand while she dabbed a damp handkerchief at her nose with the other.

The envelope was cheap, and the address had been printed in a bold, childish scrawl in pencil. Frank stared at the address for a long moment, trying to identify what was wrong. Finally, it all came together in his mind. He ripped open the envelope.

“What are you doing?” Mrs. Zimmerman cried. “That’s the last thing he wrote to his dear mother! Don’t you have any respect at all?”

Frank ignored her. He pulled the folded paper out of the envelope and scanned its contents. “Dear Ma,” it began, and that’s when Frank knew the truth.

“Did Calvin have any visitors yesterday?” he asked, interrupting the landlady, who was still expressing her outrage.

“Visitors?” she scoffed angrily. “He didn’t know nobody in town but you! Nobody ever come to see him.”

“Are you sure? Could someone else have let a visitor in without you knowing it? One of the other tenants, maybe?”

Mrs. Zimmerman stared at him for a long moment, trying to make sense of his question. “Why do you think he had a visitor?”

“Because Calvin didn’t kill himself. He was murdered.”

“CALVIN WAS MURDERED?” Sarah exclaimed in horror as she admitted Malloy to her house. She’d known the moment she saw him that something terrible had happened, and he’d been eager to unburden himself. “When? How?”

“The killer tried to make it look like a suicide again,” he said, taking off his hat and hanging it on the stand by the door. It occurred to her that he was becoming very comfortable in her home, but for some reason, the knowledge didn’t bother her as it should have.

“The boy was shot?” Sarah asked. “Didn’t someone hear it?”

“No, he was poisoned. Arsenic.”

“Oh, my.” She felt sick to her stomach. “I hardly knew him, but he was so young. He seemed like such a nice boy. And his poor mother…”

“Yeah, this is going to be real hard on her. She’ll probably blame herself for letting him come here in the first place.”

“Of course, we’re assuming she’s the kind of woman who would blame herself,” Sarah said.

“Calvin was pretty fond of her, so she must’ve been a good mother. Don’t forget, she supported the family alone after her husband left her.”

“You’re right, of course. I guess I was just hoping that she’d be the kind of person who wouldn’t take her son’s death so hard. I know the pain she’ll feel.”

Malloy didn’t say anything to that. He understood that pain, too, but he wasn’t going to discuss the subject with her. She realized they were still standing by the front door.

“Come in and sit down. Can I get you some coffee?”

A few moments later they were sitting in her kitchen. She cut him a slice of the cake Mrs. Ellsworth had brought over that afternoon to have along with the coffee she was boiling. When she set the plate in front of him, she saw that he’d spread two pieces of paper out on the table for her to see.

“Look at these, and tell me what you think. This is the suicide note.” He slid one over to her as she took her seat opposite him.

She winced as she read the words, and tears stung her eyes. She’d hardly known the boy, but he’d been far too young to die under any circumstances. “If you found this, why do you think he was murdered?” she asked when she’d finished.

He slid the other piece of paper over to her. It was the kind of letter a boy would write to his mother, telling her what he’d been doing and about the people he’d met. Malloy had made a big impression on the boy. He was a little afraid of the police detective, but Malloy had been very kind to him, even paying the rent so he could stay in his rooming house. Of course, Sarah knew this had been a ploy to make sure Calvin didn’t disappear, but even so, it was a kind one. He could have locked the boy up instead. Locking him up would have ensured he didn’t leave town, while leaving him in the rooming house was a gamble. The boy’s homesickness was palpable through his simple words, as was his love for his mother and sisters. One other thing was also obvious.

“Calvin didn’t write the suicide note,” she realized.

“What makes you think so?” he asked.

“The handwriting, for one thing,” she said, comparing the two letters. The letter to Mrs. Brown was written in a large childish hand, the letters formed carefully but awkwardly, as if by one to whom writing was an unwelcome chore. “Whoever wrote the suicide note was trying to make it look like a young person wrote it, but the printing is too small and neat to be Calvin’s.”

“How about what he wrote?”

Sarah compared the two letters more closely. “He calls his mother ‘Ma’ in the one and ‘Mother’ in the other. His grammar is much better in the suicide note, too.”

“That’s what I thought. I noticed the ‘Ma’ thing right away. And the handwriting. But if he hadn’t written the letter to his mother the day before, I might never have figured it out.”

“Or if he’d mailed it before you got to see it,” Sarah added. “I’m surprised the killer didn’t dispose of it.”

“I’m sure he would have, if he was clever enough or if he’d seen it at all, but Calvin had given it to his landlady to mail.”

“Thank heaven she hadn’t mailed it yet,” Sarah said with a sigh, laying the letters back down on the table. “Now you have two murders to solve. Do you have any idea who would have wanted to kill both Blackwell and his son?”

“We know it had to be someone who knew about Blackwell’s first family. Out of those, just about anybody who wanted Blackwell dead, and probably all of them had a good reason to.”

“That probably eliminates Letitia and Dudley,” she guessed, “since they didn’t know about Blackwell’s other family.”

“Not necessarily. We assumed Letitia didn’t know about Calvin, but we could be wrong. As you pointed out, she wouldn’t have needed a divorce to marry Dudley if her marriage to Blackwell was bigamous, but she would need to be a widow to inherit his imaginary fortune to support her and Dudley.”