U.S. Rep. Tulsi Gabbard and 87 other members of Congress on Monday called on the Department of Defense Inspector General to conduct a “full and independent investigation” into the April 22 disappearance and slaying of U.S. Army Spc. Vanessa Guillen, who was based at Fort Hood in Texas.

The 20-year-old soldier’s remains were found June 30 near the Leon River.

“Spc. Vanessa Guillen volunteered to serve our country, and proudly wore the uniform. Yet, her life and service was cut short. Since her disappearance over two months ago, we learned that she was a victim of sexual harassment, and that she was too afraid to report it,” Gabbard, a Hawaii Democrat, said in a release.

Before her disappearance and death, Guillen confided in her family that she felt unsafe in Fort Hood due to experiences with sexual harassment, U.S. Rep. Sylvia Garcia, a Democrat from Texas, said in the letter seeking an Inspector General investigation. The other members of Congress added their names to the letter.

“The U.S. military has a responsibility to ensure the safety and well-being of the young women and men that take an oath to defend our country,” the letter states. “In Spc. Guillen’s case, she was tragically failed by the Army.”

According to a criminal complaint filed by the U.S. Attorney’s Office for the Western District of Texas, 20-year-old U.S. Army Spc. Aaron Robinson told Cecily Aguilar that he killed a female soldier by striking her in the head with a hammer while at Fort Hood on April 22.

Robinson said he transferred the woman’s body off of Fort Hood and enlisted Aguilar’s help in disposing of the body, according to the U.S. Attorney’s Office.

Robinson shot and killed himself when confronted by police, officials said.