The shooting happened just before 8 p.m. Monday on Stuyvesant Avenue and Pulaski Street in Bedford-Stuyvesant, Brooklyn.
Jose Ramirez reacted immediately when his granddaughters came out of a store and the shooting began.
He said he yelled to the kids to get upstairs.
Ten-year-old Dalilah Gray, her two younger sisters and a friend then took off running, heading for the safety of their stoop where their grandfather hustled them inside.
"When my daughter lifted up her sleeve, she noticed that she had gotten shot," Ramirez explained. "The bullet just went in and out the other side."
She was rushed to Kings County Hospital where she was treated for a gunshot wound to her forearm. She remained in stable condition on Tuesday night.
Detectives are working this neighborhood for witnesses.
The shooting ended the life of 22-year-old Robert Barnes, apparently the intended target.
"It's too many damn guns on the street," Kings County District Attorney Charles Hynes said.
Hynes finds this latest homicide and the wounding of this young girl most troubling, hoping to work with community and religious leaders and police. One suggestion?
"A return to a buy back program. Police Commissioner Kelly has been very forthright in agreeing to do that sometime in the spring," he said.
Investigators were still trying to determine what led to the shooting, and who pulled the trigger.