Photos courtesy Bell County Jail and U.S. Army Fort Hood Press Center.

KILLEEN, Texas — A federal complaint charging a Killeen woman with conspiracy to tamper with evidence provides details in the disappearance of Fort Hood Spc. Vanessa Guillen.

Earlier this week, investigators discovered partial human remains near Leon River in Bell County that are believed to be that of Guillen, who was reported missing from Fort Hood on April 23, 2020. Authorities are awaiting autopsy for positive identification.

A federal complaint filed today, July 2, 2020, charges 22-year-old Cecily Aguilar with one count of conspiracy to tamper with evidence. Aguilar, according to the complaint, was in a dating relationship with 20-year-old U.S. Army Specialist Aaron Robinson who was suspected in the disappearance of Guillen.

When confronted by police earlier this week, Robinson shot and killed himself, according to authorities.

According to a federal complaint, on April 22, 2020, Guillen had left her arms room to visit another arms room at Fort Hood, which was one controlled by Robinson, to confirm serial numbers for weapons and equipment.

There, Robinson admitted to Aguilar, according to a federal complaint, to killing a female soldier at Fort Hood by striking her in the head multiple times with a hammer while in his arms room. Aguilar told investigators she later recognized that female soldier as Guillen.

According to the complaint, Robinson then placed Guillen in a box and wheeled her body out of the arms room. Nearly a month after her disappearance, two witnesses recalled Robinson pulling a large "tough box" with wheels, that appeared to be heavy in weight, from his arms room, load it into his vehicle, and drive away.

Following these witness statements, investigators obtained Robinson's consent to search of his cell phone records.

Robinson and Aguilar lied to investigators about their whereabouts on the night of Guillen's death, according to the complaint. A return of the cell phone records would later reveal Robinson and Aguilar had traveled to the vicinity of Farm-to-Market (FM) 436 and West Main Street in Belton, Texas, on or around a bridge, and then tracked north along the Leon River — all inconsistent with previous statements made by Robinson and Aguilar to investigators.

Cell phone records indicate they stayed there for about two hours and returned to the site again on April 26, 2020.

On June 21, 2020, just two days after re-interviewing Aguilar, investigators with the U.S. Army CID, Bell County Sheriff's Office, and the Texas Rangers searched along the Leon River. There, they discovering a burn site, a burned plastic tote, and disturbed earth — however, no remains were located. Investigators did note remarkably softer and moist soil below the burn site and an odor of decomposition.

On June 30, 2020, at approximately 1 p.m., contractors working on a fence adjacent the Leon River discovered what appeared to be human remains. Upon further investigation, authorities discovered scattered human remains that appeared to have been placed in a concrete-like substance and buried.

It was later that night, around 8:30 p.m., that Aguilar told investigators Robinson admitted to killing Guillen and that she had aided Robinson in disposing of Guillen's body.

If convicted, Aguilar faces up to 20 years in federal prison and a fine not to exceed $250,000.

Aguilar remains in custody and is awaiting her initial appearance in federal court in Waco, Texas, expected later this week.