Isabella Proud and her husband Jason were scientists conducting research on feral ghouls. They had a camp near Takoma Factory in Takoma Park, with a terminal describing their work. The text of her entries implies that she saw feral ghouls to be non-sentient and attracted to high radiation. Thus, she engaged in a series of actions that eventually doomed both herself and her husband Jason.
Their corpses are behind the buildings on the other side of the canal. You have to go all the way through the factory to get to it. Climb the broken metal structure in the canal and jump to the ledge on the far side. Go along and between the buildings. To the right you come to the edge of a pool. The whole area is radioactive. The camp site is at the far end. There are a few normal feral ghouls and one glowing one named Samuel, along with some minor items.