In Mrs. Sherlock Holmes: The True Story of New York City’s Greatest Female Detective and the 1917 Missing Girl Case that Captivated a Nation, Ricca revives the incredible story of a pioneering attorney.

What made you want to tell Grace Humiston’s story?

Every Wednesday, I get a coupon circular stuffed in the mailbox. The last panel on the back page always has a small photograph of a young person, usually a girl, along with the date she went missing. I wondered when missing girls became something we saw as something to consume. When I learned about Grace, I found someone who had devoted her entire life, at great risk, to solving this very problem. She was a tough-as-nails detective who only wore black, worked for free, and stood up to all types of authority. How could I not want to write about her?

How did you compensate for the paucity of official records of her cases?

There are no great archives, diaries, or even case records of Grace’s practice out there. I finally realized that like the missing girl cases she embraced, Grace was also a mystery. That pushed me to find other sources—newspapers, stories, court cases—to tell a larger story with her in the middle. Each chapter has a different main source, and thus a different perspective to it, that when combined, I hope gives us a more comprehensive view of the time and space and events Grace lived in. That being said, I make no promises. I’m not a historian or a reporter. All I can say is that I didn’t make anything up. I found tons of dialogue, personal facts, even gossip that I was able to include. Readers can trace the sources back in the notes and come to their own conclusions about what to believe.

Can you talk about the role of the media during Grace’s lifetime, and the influence it had on her career?

The media is a main character of this book. In 1917, there was no Twitter or Maddow or Megyn Kelly, but New York City had nearly 20 daily newspapers. The papers shaped the story of Ruth Cruger, and helped define her story—and perhaps the police response—in a subtle, but very important way.

What would you consider her legacy to be?

She certainly changed the way that the police, in particular the Missing Persons Bureau, operated after her solution of the Cruger case. But, to be honest, much of what we might want to be her legacy are still problems we face today, which is part of why I wanted to write about her.