She also altered and destroyed information in a Google account for Specialist Robinson, the statement said.
Ms. Aguilar initially lied to investigators about what she knew, but she later confessed to playing a role in the disposal of the body, prosecutors said in court documents.
“During the investigation into the disappearance of Vanessa Guillen, Aguilar made four materially false statements to federal investigators,” the statement said.
The federal public defender’s office for the Western District of Texas, which is representing Ms. Aguilar, declined to comment.
A sentencing date has not been set, said Michael Lahrman, a spokesman for the U.S. Attorney’s Office. Before her plea, Ms. Aguilar had been scheduled to go to trial in January.
Ms. Aguilar, a civilian, was charged with 11 counts. Before Tuesday, she had pleaded not guilty on all charges, so the plea came as a surprise, said Natalie Khawam, the Guillens’ lawyer.
“We were just looking for the day where she would just confess and admit to her crime, and the harm that was committed on this family,” she said, adding, “Today’s admission to guilt provides us some relief.”