BUNDANOON, Australia — Even into her 80s, Mary E. White thrived on the expanse of Australian rain forest she had made her home, and she told friends of ambitious plans: She was going to write her autobiography, and there were two other books she wanted to finish.

But dementia robbed her of vigor. Ms. White, an accomplished scientist who gained prominence for warnings of desert encroachment and overpopulation, soon moved into a nursing home closer to her family but far from her old home. She could not communicate, friends said, and did not recognize visitors.

Then, one evening this month, Ms. White was found dead. She was 92. Several days later, her daughter was charged with murdering her.

The accusations have stunned people who knew Ms. White and her family, as well as Bundanoon, the small town where neighbors remembered an attentive daughter who would take her mother to the salon for haircuts and stop in the cafe across the street. Many insist that whatever happened must have been motivated by compassion and love.