SANDARMOKH, Russia — The day began, like many others in her childhood years, with hours of tramping through an insect-infested forest with the family dog while her eccentric father, Yuri Dmitriev, wandered off to hunt in vain for corpses buried among the trees.

On that day more than 20 years ago, however, Mr. Dmitriev, an amateur but very determined historian, finally found the gruesome prize he had long been searching for — burial mounds containing the remains of political prisoners executed by Stalin’s secret police.

“Everything started here,” said Mr. Dmitriev’s 35-year-old daughter, Katerina Klodt, during a recent visit to the forest at Sandarmokh in Karelia, a peninsula in northern Russia. “My dad’s work has clearly made some people very uncomfortable.”

Mr. Dmitriev is now in jail, awaiting trial on what his family, friends and supporters dismiss as blatantly fabricated charges of pedophilia, an accusation that has frequently been used to discredit and silence voices the Russian authorities do not like.