Suspect in Vanessa Guillen case appears in court; remains confirmed as Guillen's

A woman accused of helping to hide the body of murdered Fort Hood Army Specialist Vanessa Guillen made her first court appearance Monday to face conspiracy charges.

Cecily Aguilar, 22, appeared via closed-circuit television in the Waco, Texas, courtroom to face conspiracy to tamper with evidence for her alleged role in the death of the 20-year-old soldier. The U.S. Attorney's office of the Western District of Texas said 20-year-old U.S. Army Specialist Aaron Robinson told Aguilar, who was his girlfriend, that he killed Guillen with a hammer on April 22 and transferred her body off the Army base, according to the criminal complaint.

Aguilar is currently cooperating with the FBI.

Robinson, who died by suicide when he was confronted by police last week, allegedly enlisted Aguilar to help dispose of the body, and the pair allegedly dismembered and buried the remains in Bell County, according to the complaint. Last week investigators found remains in Bell County. Natalie Khawam, an attorney representing Guillen's family, said Sunday the remains belonged to Guillen. The Army Criminal Investigation Command confirmed the news at a press conference Monday.

"The Armed Forces forensic examiner has determined through DNA analysis that the remains found near the Leon River are in fact those of Vanessa Guillen," Major General Scott Efflandt said.

Aguilar did not make any statement other than to acknowledge the charges against her, and she didn't enter a plea. She's due back in court on July 14 for a preliminary hearing to determine bond. Aguilar is being held at the Jack Harwell Detention Center in Waco, a U.S. Marshals representative confirmed to ABC News.

If convicted, she faces up to 20 years in federal prison and a maximum $250,000 fine, the U.S. Attorney's Office said.

Lewis Berray Gainor, the federal public defender assigned to Aguilar, declined ABC News' request for comment.

According to an updated criminal complaint, Aguilar cooperated with the FBI in the case by allowing investigators to tape a phone call between her and Robinson on June 30, during which Robinson didn't deny any of the alleged crimes. Aguilar also assisted law enforcement in locating Robinson before he was confronted and died by suicide, according to the document.

Guillen's family has called for a congressional investigation into Guillen's death. Nearly 100 lawmakers have also called for an independent review of Fort Hood's handling of Guillen's disappearance. On Monday, the House Oversight Committee announced it has requested a briefing on the Army's response and investigation into the disappearance and murder of Guillen.

While the Army hasn't commented on a possible motive, Khawam previously said investigators told her that Guillen and Robinson had an argument in the base's armory after she discovered his alleged affair with the estranged wife of a former soldier.

The family has also alleged that a man had walked in on Guillen and watched her as she showered, but the Army said it didn't hasn't found evidence of sexual harassment. On Monday, Efflandt said Army CID will complete that investigation and "take actions against those findings."

“Please know that every person who raises their right hand to serve their family in their country in uniform deserves to be safe and treated with dignity and respect to the victims of sexual harassment assault," he said. "We hear you. We believe you. And I encourage you to come forward."

ABC News' Mike Repplier and Ben Siegel contributed to this report.