A former airman stationed at Dover Air Force Base is going on trial on a murder charge in the 2012 death of a 21-month-old boy who was left in his care.

The trial of Justin Corbett was scheduled to begin Tuesday with jury selection. Corbett is charged with first-degree murder by abuse or neglect, recklessly causing the death of a child.

Authorities say Corbett was caring for Evan Dudley in November 2012 while the boy's mother, also a Dover Air Force Base airman, was deployed. Police say Corbett called 911 to report that Evan was unresponsive after falling down stairs.

The boy died at a hospital a few days later. His death was ruled a homicide by blunt force trauma.

Corbett has denied killing the boy.