Before the reported slaying of Army Specialist Vanessa Guillen last year, the Texas soldier told her mother that she was being sexually harassed and reported it to her superior, according to U.S. Army documents released Friday.

Based on the report, Army investigators uncovered that Vanessa Guillen was sexually harassed by a superior noncommissioned officer in her unit and not by the man suspected of killing her. However, the officer determined was not named in the report.

According to The Hill, the summary of the investigation indicated that Guillen reported that she experienced sexual harassment on two occasions. And in both instances, her supervisor failed to report the incident. Other leaders were also not able to take appropriate action regarding the situation.

But despite the reports, the Army noted that there is no evidence that the sexual harassment was related to Guillen's death.

RELATED ARTICLE: Slain Soldier Vanessa Guillen Honored With Memorial Gate at Fort Hood

Suspects in Vanessa Guillen's Death

Vanessa Guillen was last seen on Apr. 22 last year, before Spc. Aaron Robinson allegedly hit her in the head with a hammer multiple times inside an armory room in Fort Hood, Texas.

The suspect reportedly could not dispose of Guillen's body by himself, so he contacted his girlfriend, Cecily Aguilar, and asked her to help. 

The two allegedly took Guillen's body to the Leon River, about 20 miles away from the Army base. They buried Vanessa Guillen's remains near the river.

Army officials were not able to confirm as to what was Robinson's motive for killing Guillen. The remains of the 20-year-old female soldier were found last Jun. 30.

The day that Guillen's remains were found, Robinson killed himself while the police tried to arrest him, CrimeOnline reported.

Despite not having found any credible evidence to conclude that Robinson sexually harassed Vanessa Guillen, the latest report indicated that he sexually harassed another female soldier in Fort Hood between April to September 2019.

Army's Actions on the Sexual Harassment

In a statement released Friday, the Army said five current or former leaders of the 3rd Cavalry Regiment in Fort Hood had been fired because of the new report. Three of them were to receive General Officer Memorandums of Reprimand.

Another eight noncommissioned and commissioned officers had further action referred against them, with one to be fired. The punishments and firing mark a total of 21 personnel to be disciplined because of the investigations that started after Vanessa Guillen's disappearance.

Army Forces Command Chief of Staff Maj. Gen. Gene LeBoeuf shared on Friday that none of their actions will bring Guillen back. But the official added that her memory drives them to be better. 

He added that the death of the Texas soldier would drive the Army forward to affect change for the people, communities, and nation. 

"You are witnessing action for culture change," he noted. The Army has confirmed that Guillen was sexually harassed after the investigation team reviewed over 6,000 emails, analyzed some 11,500 pages of documents, and interviewed 151 witnesses.

In one incident, the report said that the female soldier was in her troop orderly room when one of her supervisors made an inappropriate sexual comment in Spanish, which translates as a solicitation for her to participate in a "threesome."

The said supervisor also specifically targeted and called her out in front of her peers, and made an example out of her. After a supervisor noticed a marked change in her demeanor, Vanessa Guillen and another soldier told the official about the inappropriate sexual comment.

Between Sept. 16, 2019, and Oct. 9, 2019, two soldiers reported the incident to Vanessa Guillen's unit leaders, but they failed to launch an investigation.

READ MORE: Vanessa Guillen's Entire Fort Hood Chain of Command Fired

 WATCH: Army Report Says Vanessa Guillen Was Sexually Harassed Before Her Death - From CBS Evening News