“The police have hands, ears, eyes, legs, noses, and mouths just the same as we do. They can gather the facts and draw conclusions just the same as we can. It isn’t up to us to prove that girl innocent. It’s up to the police to show that she’s guilty. If we can account for the circumstances by some other explanation which doesn’t leave any loose threads dangling, that’s all we need to offer to a jury. That’s the law.”

“Well,” I said, “that’s not an exact statement of the law, but it’s close enough.”

“Now then,” she demanded, “do you want to get Alma Hunter out of this or not?”

“Yes.”

“All right then. Keep your mouth shut, and let Auntie Bertha do the talking.”

The cab pulled up in front of Sandra’s apartment house. A police guard was stationed in the lobby. Apparently the few early morning stragglers had no inkling of what had happened. There was no outward indication of a homicide.

Bertha Cool paid off the cab and barged up to the apartment house. The officer said, “Just a moment. Do you live here?”

“No.”

“Where are you going?”

“To call on Sandra Birks.”

“What’s your name?”

“Bertha Cool, head of the Cool Detective Agency. This is one of my operatives.”

“What do you want?”

“To see Sandra Birks.”

“What do you want to see her about?”

“I don’t know. She wants to see me. What’s the matter? Is she under arrest?”

“No, not under arrest.”

“It’s her apartment, isn’t it?”

“Oh, go on up,” he said.

“Thanks. I intend to,” Mrs. Cool announced.

I tried to be polite about the door, but she beat me to it, grabbed the knob and flung the heavy door back as though it had been made of cardboard. She strode on in, and I came along in her wake. We took the elevator to the fourth floor. Sandra Birks flung open the door as I tapped gently on the panels.

“It took you long enough to get here.”

Bertha Cool said, “We didn’t want to run into the police.”

“There’s a guard downstairs.”

“I know.”

“Did he try to stop you?”

“Yes.”

“How did you get by?”

“Walked by.”

“You told him you were a detective?”

“Yes.”

“Would he let anyone in who wasn’t a detective?”

“How the hell do I know, dearie? He’s a cop. You can’t tell what a cop will do.”

Sandra bit her lip and frowned. “I’m expecting a young man—a friend of ours—I wonder if they’ll take him into custody—”

“Better call him up and head him off,” I said.

“I think they have my line tapped. I think they’re leaving me here as bait for a trap.”

“What sort of a trap?”

“I don’t know.”