More than 100 members of Congress have signed on to a letter demanding that the United States conduct an independent investigation into the Israeli forces’ killing of Turkish American activist Ayşenur Ezgi Eygi earlier this month in the occupied West Bank, after the military alleged that its soldiers likely shot the young pro-Palestinian woman on accident.

The Tuesday letter was drafted by Rep. Adam Smith, a Democrat representing Eygi’s home state of Washington. A Seattle resident and recent University of Washington graduate, the 26-year-old activist was shot dead by Israeli forces on Sept. 6 while she was volunteering as an international observer for Palestinians engaging in a weekly protest against an illegal settlement expansion in the occupied territory’s village of Beita.

After news of Eygi’s killing spread throughout the international community and the U.S., the Israeli Defense Forces said it would conduct a preliminary investigation into the shooting — a rare move by the military that even more rarely results in accountability. Upon conclusion of said preliminary investigation, the IDF stated that it was “highly likely” that Eygi was “hit indirectly and unintentionally by IDF fire which was not aimed at her” during a “violent riot.”

The letter said that lawmakers are “deeply disturbed” by the IDF’s probe, which contradicts credible eyewitness accounts from fellow volunteers and Palestinians on the ground, as well as a recent Washington Post investigation that corroborates the accounts with additional interviews and photo and video evidence. Eygi’s family also called the Israeli probe “wholly inadequate.”

The evidence suggests that an Israeli sniper intentionally shot an unarmed Eygi in the head from an elevated position while she was in a quiet olive grove more than 200 yards away from Israeli forces, about 30 minutes after clashes between Palestinian residents and Israeli soldiers subsided and most protesters had retreated.

The U.S. must take the evidence into consideration and launch an independent probe into whether Eygi’s killing was a homicide, the lawmakers said. The Biden administration and Congress have continued to provide unconditional military and diplomatic support for Israel, which has been accused of repeatedly violating international law.

“To walk away without asking further questions gives Israeli forces unacceptable license to act with impunity. There must be accountability for Ms. Eygi’s death,” the letter stated. “We therefore call on the White House, State Department and Department of Justice to lead an independent, thorough, credible and transparent investigation into the killing of Ms. Eygi. This investigation should include all evidence found and rationale for how findings were determined in a written report to the family.”

The letter, which gives the departments until Oct. 4 to provide the written report, is followed by eight pages of signatures from more than 100 lawmakers in both congressional chambers.

Eygi’s family expressed appreciation for the letter, stressing their long-repeated calls for both a thorough independent investigation and the release of all evidence to her loved ones — moves that are “the bare minimum” the family said they should expect from the Biden administration.

“As Ayşenur’s family, we know the United States is more accustomed to providing impunity to Israeli military and officials instead of justice for the family members impacted by Israel’s criminal actions,” the family said in a Tuesday statement. “The U.S. has never held Israeli actors accountable for its killings of American citizens, and the killings of tens of thousands of Palestinians whose lives were violently taken from them by U.S.-supplied weapons.”

Spokespersons for the White House and State Department did not respond to HuffPost’s request for comment. A spokesperson for the Justice Department confirmed receipt of the letter, but declined to comment on the substance.

Despite calling Eygi’s killing “unacceptable,” President Joe Biden appeared earlier this month to support Israel’s conclusion, saying that the American woman’s death was “the result of a tragic error resulting from an unnecessary escalation.” Biden had also not yet called Eygi’s family, who found the president’s response “insensitive and false.”

Palestinians in the occupied West Bank have faced a surge of settler and military violence ever since Israel launched its almost yearlong offensive in Gaza, which began after Hamas militants killed about 1,200 people in southern Israel and captured more than 200 hostages. As of Monday, the United Nations says Israeli forces have killed more than 41,000 Palestinians and wounded more than 96,000 in Gaza — while in the West Bank, soldiers and settlers have killed a total of nearly 700 Palestinians.