To prepare the nutshells for exhibition at the Smithsonian, O’Connor has led a months-long effort to conserve the dioramas. The work, she says, has been a bit like detective work itself. She looks for subtle hints like glue residue to match up, say, an object that has fallen off of the shelf where it originally stood. Because any object out of place can in fact be an important clue to the murder, every move requires consultation with Maryland’s medical examiners, who have the solutions to the nutshells.

“It is one of the most challenging things I have ever tried to work on,” says O’Connor. The sheer number of materials in the nutshells add to the challenge. Materials have “inherent vice,” or a natural tendency to degrade over time. The plastic panes of the nutshells’ windows, for example, are especially prone to warping. O’Connor also had to figure out how to preserve a nutshell that features a burnt house. (Lee literally had a blowtorch taken to it.) She ended up borrowing techniques from archaeology used to preserve burnt wood.

A big part of the conservation project has focused on lighting. Lee used the incandescent bulbs available in her time, which cast a beautiful warm glow but have the disadvantage of heat. Heat causes damage. The painted linoleum in one nutshell had cracked and curled, in part, O’Connor thinks, because of the heat of the lightbulb above it.

To be in the Smithsonian exhibit, the lights would have to be on hours each day, which would have caused too much damage. So the team replaced 70 incandescent bulbs with custom-made LEDs, matching the quality of light without the heat. It’s possible now because of recent advances in LED technology. “Just a few years ago, we couldn’t have achieved this quality with LEDs,” says Scott Rosenfeld, a lighting designer at the Smithsonian. The 80-year-old dioramas now have a state-of-the-art lighting system.

The trickiest nutshell to restore was the lost nutshell, which features a dead man on his couch. The solution is completely lost. To make matters worse, when it was taken out of the attic where it was found, it was tipped over, displacing many of the objects Lee had carefully placed inside as clues. There was dirt all over the living-room floor. The bannister for the stairs had fallen down, which led some to suspect it was the murder weapon. But then O’Connor discovered that the bannister is supposed to be intact. They glued it back on.

When I stopped by the unfinished exhibit, O’Connor and Atkinson were still discussing where to place an object that had come loose and they suspected was a key clue. (I’m being purposely vague to avoid spoilers. I will say, you would have to look very, very carefully to even notice.) I asked O’Connor if she had solved the death after spending so many hours with the lost nutshell. She laughed and demurred. Visitors to the Smithsonian’s Renwick Gallery will have the opportunity to test their own detective skills.

The Renwick Gallery specifically showcases craft and decorative arts. Atkinson told me she was particularly pleased to exhibit Lee’s nutshells because museums have traditionally focused on studio craft, which has been so dominated by the work of white men. Half a century after her death, Lee is still transgressing in the world of men.