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.

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.

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.

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