A librarian on Chicago’s North Shore was presented with a mystery, found in the building’s walls. When a crew was renovated the HVAC system, they found a black purse, the Daily North Shore reports.

Inside, there were a few objects—a lipstick, an earring, a pencil, two photos, and a reservation ticket for the dentist’s office, on a Tuesday, October 11.

The photos showed a younger girl and an older woman, but most helpful clue so far was the ticket for the dentist’s. It turns out that there was only one Tuesday, October 11 in history when dentist Arthur S. Dunn was at the number listed on the card. That was in 1966.

The card also had a name—Ellen Pritikin. Between the photos and that last clue, the library is hoping to find the original owner.

How the purse ended up in the wall, though, will stay a mystery. The library has been renovated enough that it’s just not clear how the purse ended up in the wall and stayed there for more than 50 years.