Sandy Springs police say the boy was alone playing with the .45-caliber handgun when it went off and shot him in the arm.

Police say they arrested the child's mother, Shanice Harris, 26, and her ex-boyfriend, Marcus Phillips, 30, for allegedly lying to investigators. Both have been charged with obstruction of a law enforcement officer. Phillips also was charged with possession of a firearm by a convicted felon.

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Police say Phillips carelessly left his gun on the bedroom dresser, where the child found it.

"Apparently, the mother told detectives that she found her child outside laying in the bushes with a gunshot wound in his arm," said Ronald Momon with the Sandy Springs Police Department.

WSB-TV's Tyisha Fernandes spoke to neighbor Itzel Gomez after the shooting. Gomez says she saw the child with "blood everywhere."

Police obtained a search warrant and it took them several hours to find the gun, which was hidden inside an apartment.

Police say they questioned a 15-year-old as a potential witness.

The 4-year-old's grandmother, Mary Silverman, says it's a miracle that her grandson is alive.

"He could have shot himself in the head or could've lost enough blood to bleed out," Momon said.

The boy was rushed to Scottish Rite hospital with non-life-threatening injuries.