A soldier moves a traffic cone as cars wait to enter Fort Bliss in El Paso, Texas, Tuesday Sept. 9, 2014. The Army is ramping up security at Fort Bliss, its sprawling West Texas post near the US-Mexico border. The tighter security is to include random vehicle checks and access limited to Defense Department personnel at some of its gates. (AP Photo/Juan Carlos Llorca)

By Lisa Maria Garza

DALLAS (Reuters) - A Fort Bliss, Texas, soldier beat his 2-year-old daughter to death after he became upset that she soiled her diaper, police said on Monday.

Dartarious Graham, a 20-year-old U.S. Army specialist, was arrested by El Paso police and charged with capital murder in the death of his daughter. Peyton Graham was found unresponsive with suspicious injuries in her father's apartment and later died at a hospital on Saturday, police said.

Graham's cousin, Robert Franklin, 19, witnessed the beating in the child's bedroom and walked away without calling for help, police said in a statement.

The child's mother, Elizabeth Graham, 23, was not home at the time of the incident. Investigators learned the father had a history of beating the child and that the mother had failed to protect her and report the abuse, police said.

The mother and the cousin were also arrested and charged with "injury to a child by omission," meaning that they failed to take action to prevent the child's injury.

All three are being held in El Paso County jail. Dartarious Graham, whose bail is set at $250,000, could face the death penalty or life without parole if convicted.

(Reporting by Lisa Maria Garza in Dallas; Editing by Mary Wisniewski and Doina Chiacu)