Rachel Corrie, 23, from Olympia, was crushed to death March 16 while trying to block a huge army bulldozer destroying a Palestinian home in Rafah, near the Gaza-Egypt border.

The Israeli military said the bulldozer driver could not see Corrie because of its limited view. Others, activists and some Israeli officials, have disputed that.

Corrie was working with a group called the International Solidarity Movement. Participants often place themselves between Israeli forces and Palestinians civilians.

Nearly 50 members of the 435-seat U.S. House of Representatives have signed a bill calling for an independent investigation, she said.

"I need to know if Rachel's death was intentional or accidental," she said, her voice breaking. "I just want to know the truth."

Two other International Solidarity volunteers were shot shortly after Corrie was killed.

On April 5, Brian Avery, 24, of Albuquerque, N.M., was shot in the face during fighting in the West Bank town of Jenin.

On April 11, Thomas Hurndall, 21, of Britain, was shot in the head by Israeli troops as he helped children to safety in the Gaza Strip. He remains brain dead in England.