WACO, Texas (CBSDFW.COM) — The only living suspect in the disappearance of Fort Hood Army Spc. Vanessa Guillen is scheduled to appear in court today.

Cecily Aguilar — who is being held in the Bell County Jail — is charged with conspiracy to tamper with evidence. The preliminary hearing for the 22-year-old will be held in a Waco courtroom.

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The second suspect in the disappearance of Guillen, 20-year-old Spc. Aaron David Robinson, used a gun to commit suicide as police in Killeen tried to approach and speak to him.

(credit: Bell County Jail)

Aguilar, the estranged wife of a former Fort Hood soldier, was Robinson’s girlfriend.

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According to investigators, Robinson told Aguilar that he killed Guillen by hitting her in the head with a hammer and then moved the soldier’s body from Fort Hood to a remote location in Bell County. Aguilar is accused of helping him hide the body.

On Sunday a lab positively identified the human remains found in a shallow grave about 20 miles from Fort Hood, near the Leon River, as Spc. Guillen. The 20-year-old soldier had been missing since April 22 and was last seen in the parking lot outside of her barracks at Fort Hood. Her remains were found June 30.

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If convicted, Cecily Aguilar faces up to 20 years in prison and a maximum $250,000 fine.