HOUSTON — More than two months after a young soldier went missing from a Texas military base, U.S. Army investigators said this week that they suspect foul play related to her disappearance and have opened a separate inquiry into allegations that she was sexually harassed by a supervisor.

Vanessa Guillén, 20, was last seen on the morning of April 22 in the parking lot outside her regiment headquarters on Fort Hood Army base in Killeen. Investigators found her car keys, her barracks room key, Army identification card and wallet at the armory where she had worked the day before she disappeared.

“If they find my daughter dead, I will shut down this base,” said her mother, Gloria Guillén, during a news conference at Fort Hood this week. Her remarks came after a meeting with command staff. Gloria Guillén fell ill after watching searchers comb a river near the base for her daughter. “I want my daughter alive,” she said. “That girl is my life.”

The private’s family reported her missing hours after they last communicated with her and friends could not find her on the base. The family has pressed the U.S. Army and federal lawmakers to pay attention to the case, enlisting the help of Rep. Sylvia Garcia (D-Tex.), a Latino civil rights organization, Hispanic celebrities and Spanish speakers on social media to amplify the story.

Guillén’s family has been critical of military command, accusing it of indifference and failing to shut down Fort Hood in the hours after she disappeared. Vanessa Guillén complained to friends and family about being sexually harassed by a sergeant, according to her family and their attorney, but there is no record of any formal complaint. Army investigators said the harassment allegations “did not produce any viable leads” related to the soldier’s disappearance. They have also said they investigated an alleged incident of verbal harassment against Guillén that they have been unable to corroborate.

Army Col. Ralph Overland, commander of Guillén’s 3rd Cavalry Regiment, said in a statement that the Army takes “allegations of sexual harassment very seriously,” and a separate administrative review of the harassment allegations will take place independent of the criminal investigation into Guillén’s disappearance.

The Criminal Investigation Command (CID) — the military’s equivalent of the FBI — said its investigators have interviewed more than 300 people and have not ruled out anything, according to spokesman Christopher Grey. They began searching for Guillén with the help of several agencies, including the FBI, he said.

“We will not stop until we find Vanessa,” Grey said in response to emailed questions. “Our agents are working around-the-clock and have conducted a tremendous amount of investigative work.”

More than 500 soldiers have searched for Guillén on the ground and in water, using drones and helicopters in and around Fort Hood, but have found nothing, said Fort Hoodspokesman Chris Haug. Guillén is as important to the Army as she is to her family, he added.

The military also posted a $25,000 reward for information about Guillén’s whereabouts. Grey, however, said it is not uncommon for the CID to open cases for soldiers who disappear under suspicious circumstances.

“It says the Army criminal investigators are serious about finding [Guillén], they are serious about looking, and serious about taking this case seriously,” said Maggie Haswell, a former Air Force security specialist who has tracked more than 100 missing service members since 2013. She has been in touch with Guillén’s family.

“They do not believe she left of her own free will.”

The family and congressional lawmakers met with Fort Hood command staff and investigators on Tuesday to discuss the case. Natalie Khawam, an attorney for Guillén’s family, said she was pleased to have more answers after weeks of hearing nothing but was angered by discrepancies in the statements Army investigators made to the family.

Khawam said the Army initially said Guillén had reported for a 3 p.m. check-in with her supervisor, but, when pressed, admitted the report was erroneous. The Army did not say why the report was wrong.

Khawam said she emailed questions to investigators before the meeting and was promised a timeline and records. But when they arrived, the attorney said she could not obtain specific details, such as who called Guillén into work that day and the location of her cellphone. Khawam said she will file FOIA requests and subpoena phone records herself.

“Their answers were not justified. It was bogus. How dare you not be more transparent with the family?” said Khawam, who has worked on previous military sexual assault cases and is advocating for tougher legislation in Congress. “I think a lot of people dropped the ball. They were being disingenuous about their efforts to find her.”

The meeting, Khawam said, felt staged and devolved into a tense exchange because investigators declined to provide more details, fearing it could jeopardize the case.

“I think the most important part is that they are using the words now: ‘foul play,’ ” Garcia said at a news conference following the meeting. They “are looking at potential criminal activity to have occurred. The question is: who, what and when?”

In a statement, base command said it appreciated the opportunity to show Guillén’s family, attorney and lawmakers her work area and the lot where she was last seen.

Guillén’s disappearance is the latest in a series of missing persons cases in recent years at Fort Hood, one of the Army’s largest military installations. Gregory Wedel Morales went missing in August 2019, days before his expected discharge. His remains were found earlier this week, buried in a field in Killeen.

“Maybe if they had just been searching from the beginning, we’d have some answers,” his mother, Kim Wedel, told Tulsa’s ABC affiliate. “You know, he didn’t bury himself in a field on his own.”

The Army declares absent service members as having gone absent without leave, or AWOL, after 24 hours of failing to report for duty. Commanders are required to look into individual cases, but critics say the search is not exhaustive because of the stigma the label carries. Families are often frustrated by what they perceive as delays and a lack of interest by the military. After 30 days, the Army drops the missing soldier from its roster or classifies them as a deserter, and the vacant position is quickly filled.

“They don’t look for them like they should,” Haswell said.

Patrice Wise-Franklin hired a private investigator and felt dismissed by Army commanders when she pressured them to keep searching for her son, Dakota Stump, after he went missing from Fort Hood in October 2016. Investigators followed false leads before finding his body three weeks later beneath his car in a wooded area on the base. He died in a single-vehicle car accident.

“It felt like it was a joke to them,” Wise-Franklin said. “Until Fort Hood makes the hard decision on changing the protocol on how they handle missing soldiers, they are going to keep having this happen with the same outcome.”

Haug, the Fort Hood spokesman, said the Army searches for missing soldiers the moment they disappear. Haug said there is a process by which supervisors are tasked with searching the soldier’s belongings, residence and work to find the missing soldier as the case goes up the chain of command. Grey said the CID routinely opens missing soldier cases.

In Guillén’s case, her older sister, Mayra, was the first to notice something was wrong. Her sister was scheduled to go hiking with friends on April 22 but was unexpectedly called into work on her day off at the armory, family said, where she works with small arms and artillery. The CID said most soldiers have been in their barracks during the pandemic and are routinely called in “if something had to be accomplished.”

The sisters are close and communicate often. When Vanessa Guillén stopped replying between 11:30 a.m. and 1:30 p.m., her sister was alarmed. Others tried to text the soldier but the messages were not delivered and calls went straight to voice mail. Mayra Guillén said she reported her sister missing to command and drove three hours from Houston to Killeen to start searching, but she could not get on the base until the next morning.

The League of United Latin American Citizens, the oldest Latino civil rights organization in the country, has backed the family and denounced what it calls the “total and reckless mishandling” of the investigation by the Army CID. It is urging Latino families across the country to stop their children from enlisting in the military until Guillén is found.

Alex Horton in Washington contributed to this report.