Private Connell Williams pleaded not guilty to the charge of first degree murder.
This is the sixth full day attorneys have filtered through potential jurors.
Williams is on trial in the US Courthouse in Lawton for the May 2011 death of Marcus Holloway, the son of his girlfriend Candice Holloway.
She told investigators her son was fed only rice cakes, cereal bars, and water to drink on most days and was beaten severely if he stole food.
She was sentenced to 30 years in prison, and is expected to testify in Williams' trial.
According to court records, federal prosecutors are seeking the death penalty.