Miracle Johnson, 10, was playing in a bedroom with several young relatives visiting for Christmas when she was shot once, the Polk County Sheriff's Office said. She was pronounced dead at the home about 50 miles southeast of Tampa.
Investigators have not said whether they believe the shooting was intentional. No charges have been filed. They have not said who owns the gun or how the children got it.
The Associated Press is not naming the boy because he is a juvenile. His 5-year-old sister was also in the bedroom when Miracle was shot, the sheriff's office said.
Miracle lived at the home with her great-grandmother, Authur Ree Murry, 79. Murry was in the kitchen at the time and Sheriff Grady Judd said she was distraught over the shooting.
"Quite frankly, I think we're all distraught this afternoon," Judd said.
Donna Wood, a spokeswoman with the sheriff's office, said investigators are interviewing the boy and others in the home.
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