HAIFA, Israel  Seven years after an American student, Rachel Corrie, was killed in Gaza by an Israeli military bulldozer she tried to block, becoming a global symbol of the Palestinian struggle, her parents and her older sister sit in an Israeli court in this northern city with two hopes: to confront the men who ran over her and to prove that the army investigation into her death was flawed.

On both counts, it has been a frustrating effort. To guard their identities, the bulldozer operators are called only by their initials and testify behind a screen, disembodied voices claiming vague memories. The Corrie lawyer presses them with props: “Mr. A,” he said to a commander this past Thursday, arranging a plastic toy bulldozer, an orange lump of putty and a Raggedy Ann doll, “Where was she when you saw her?”

Mr. A’s answer differed markedly from that of Mr. Y, the driver of the bulldozer who testified two weeks earlier, although both denied seeing her before she was crushed under their vehicle. The army said Ms. Corrie’s death was an accident. The Corries believe the drivers either saw Rachel or were so careless toward the protesters as to be criminally negligent.

On the blond wooden benches of the Haifa District Court, the Corries take notes, volunteer translators whispering in their ears. They have mostly been here, away from their Olympia, Wash., home, since their civil case claiming the intentional and unlawful killing of their daughter began in March and there is no end in sight, with sessions already planned for January. They are exhausted but unbent.