Vanessa Guillen, a 20-year-old US Army specialist at Fort Hood in Texas, went missing more than two months ago.

After a weeks-long search, a lawyer for the Guillen family confirmed that human remains found on June 30 near her former base were those of the missing soldier.

The main suspect in the case, a fellow US Army specialist named Aaron Robinson, who was also based at Fort Hood, committed suicide last Wednesday as police closed in on him.

Another suspect, Cecily Aguilar, Robinson's girlfriend, was charged last Thursday with "conspiracy to tamper with evidence."

Since Guillen's disappearance on April 22, her loved ones have said repeatedly that she was sexually harassed at the military base.

"She was afraid to report it," her sister Lupe told ABC News.

"She reported it to her friends. She reported it to her family. She even reported to other soldiers on base," she said.

"But she didn't want to do a formal report because she was afraid of retaliation and being blackballed, and she, like most victims, just tried to deal with it herself."

Guillen's case has been taken up by several prominent public figures, including the presumptive Democratic nominee for president, Joe Biden.

"We owe it to those who put on the uniform, and to their families, to put an end to sexual harassment and assault in the military, and hold perpetrators accountable," Biden said.

According to the Justice Department, Robinson told Aguilar he had killed Guillen with a hammer blow to the head, and the pair took her body to a remote site to dispose of it.

According to Guillen family attorney Natalie Khawam, Guillen had planned to file a sexual harassment complaint against Robinson.

"We believe he murdered her because she was going to report the sexual harassment," Khawam said.

She said sexual harassment was "epidemic" in the military and called for Congress to investigate.

"You can't turn a blind eye anymore," she said.

Senator Kirsten Gillibrand, a Democrat from New York, called for the Pentagon inspector general to conduct an investigation.

Guillen's case "raises serious and alarming questions about the Army's ability to prevent sexual harassment and assault, respond to criminal acts and provide justice for victims and their families," Gillibrand said in a statement.

"There must be a full and thorough investigation into Guillen's disappearance, both to deliver justice and to initiate change in the Army's approach to sexual assault in the military and the culture that enables it."

Damon Phelps, the official in charge of the Army-led investigation, told a news conference last week that for the time being, there was no "credible information" to support the harassment allegation.