Israel cannot be trusted to conduct a reliable investigation of its raid of the Gaza-bound aid flotilla, the family of Rachel Corrie, an American human rights activist who was killed in Gaza, wrote to U.S. United Nations envoy Susan Rice earlier this month.

Corrie, a U.S. citizen, was 24 when she was struck and killed in 2003 by a bulldozer as she and other activists tried to stop Israel razing homes in Rafah by using their bodies as human shields.

The driver said he didn't see her, and the Israel Defense Forces has ruled her death an accident - a version her parents reject.

In the letter obtained by Haaretz, Cindy and Craig Corrie referred to the May 31 raid of the Gaza flotilla which resulted in the deaths of 9 activists, saying they wished to express their "continuing sorrow and outrage over the recent killings and injuries aboard the Mavi Marmara and other vessels that sailed with the Freedom Flotilla to break the siege of Gaza."

"We write also to inform you," the Corrie family added, "of the longstanding, U. S. government position that Israel has failed to conduct a thorough, credible and transparent investigation into our daughter’s killing and that after repeated attempts at the highest levels, U.S. officials have been unable to secure such an investigation."

Rachel Corrie's parents' then said they believed it was "important that Israel’s raid on the flotilla be investigated independently," adding that "while the Israeli Government has a responsibility to conduct its own internal investigation, our experience leads us to believe that Israel cannot be counted upon to reliably investigate itself."

According to the letter, an Israeli court found what it called "serious grounds for suspicion that the cause of death … was the result of a crime," but that instead of following through with the case, the court instead "closed Rachel’s file with no further action and without the required report of the autopsy results or any other report of evidence or inquiry from the Military Police or other investigators."

"Our personal experience has made it all too painfully clear that the Israeli government is unable or unwilling to adequately investigate itself and that the U.S. does not, apparently, have the ability or will to compel such an investigation," the Corries said.

The letter to UN representative Rice concluded with Cindy and Craig Corrie urging the U.S. to support a "truly independent investigation into the raid on the Mavi Marmara, one that is complete, impartial, and trustworthy."

"We add our voice to those calling upon the United States and the international community to insist that an independent investigation be conducted," they added.