" How do we know that?” Lucy was frowning. “By inference. She did not attach a piece of paper to a blanket with a bare pin and wrap the blanket around the baby. Mr. Goodwin found a tray half full of safety pins in her house. But he found no rubber-stamp kit and no stamp pad, and one was used for the message on the paper. The inference is not conclusive, but it is valid. I am satisfied that on May twentieth Ellen Tenzer delivered the baby to someone, either at her house or, more likely, at a rendezvous elsewhere. She may or may not have known that its destination was your vestibule. I doubt it; but she knew too much about its history, its origin, so she was killed. "
― Rex Stout , The Mother Hunt (Nero Wolfe #38)