An Oklahoma City man has pleaded guilty to killing the mother of his unborn child.

No plea agreement was in place when 21-year-old Eric Kennedy Phan entered his guilty pleas Thursday on two counts of first-degree murder.

Prosecutors did not seek the death penalty, so Phan will face a sentence of life in prison either with or without parole. His sentencing is scheduled for Oct. 17.

Phan was arrested in November after Lauren Barnes, 20, disappeared. Her body was found in a shallow grave at Oklahoma City's Stinchcomb Wildlife Refuge.

She was nearly six months pregnant.

A state medical examiner said Barnes died of asphyxiation.