Years ago, I discovered that my grandmother had a step-grandmother who had never been mentioned. For a long list of reasons, I never mentioned the step-grandmother to my own grandmother.
However, I did learn where the step-grandmother was buried. A few months later, my Dad and I had cause to go close to the cemetery on a trip somewhere else and I asked if we could stop for a few minutes to see if I could find the stone.
There was no stone.
Dad mentioned to Grandma the next morning that we had stopped at said cemetery. Grandma later very directly asked me WHO I was looking for in THAT cemetery. Grandma probably knew who I was looking for as there are NO other family members buried there.
Her pointed question and the look on her face told me that she knew darned well who was buried there and whose stone I was looking for.
Sometimes clues aren't always written, spoken, or photographed.