INDIANAPOLIS -- A 5-year-old boy fatally shot his 4-year-old sister with a semiautomatic handgun he had taken from a bookcase to play with, police said.

The shooting happened just after 10 a.m. Sunday in the 6100 block of Massachusetts Avenue, on Indianapolis' northeast side.

Police found Makayla Booher on the floor of an upstairs bedroom with a gunshot wound to the head. The gun was found on the floor nearby, police said.

"I just heard a pow. I asked my wife, 'Did you hear that?' and she said, 'Yeah, I heard it, too,'" said neighbor Billy Adell.

Officers said the boy had pulled a chair up to a bookcase and grabbed the gun, which belonged to father, James Booher, 24, from the top shelf.

Police said the boy took the gun upstairs, pointed it at his sister and pulled the trigger.

Adell and his wife said they saw medics and police race inside the home and that an officer came out with the girl in his arms.

"There was like a flannel wrapped around (her) and (she) was bleeding from the head," Adell said.

Makayla Booher was pronounced dead at the scene. Police said the boy couldn't have known the consequences of pointing a gun at his sister and pulling the trigger.

The boy's father, a 15-year-old stepsister and an aunt were home at the time, according to officers. Police said James Booher and the children's mother are separated.

Child Protective Services took the boy and his stepsister into custody. James Booher could face a neglect charge.