A 4-year-old and 2-year-old were treated for gunshot wounds after the elder child found an unattended gun in a Marietta apartment Monday and fired it, hitting them both, authorities said.

Marietta police arrested 23-year-old Johnnel Green on multiple charges related to the injuries, accusing the Riverdale man of leaving the loaded weapon on a patio chair at the Magnolia at Whitlock apartments on Whitlock Avenue.

The children, who are cousins, were taken to Wellstar Kennestone Hospital about 12:30 p.m. Monday, Marietta police spokesman Officer Paul Hill said. Investigators were called and determined the 4-year-old got hold of a handgun and fired a single shot, striking both children, Hill said.

Police did not specify the relationship between Green and the two children, but the family told Channel 2 Action News that he is a family friend. They confirmed the 2-year-old has been released from the hospital, while the 4-year-old was moved to a Children’s Healthcare of Atlanta location.

Green is facing two counts of cruelty to children, one count of reckless conduct, one count of tampering with evidence and one count of possession of a firearm by a felon. An arrest warrant obtained by Channel 2 accuses Green of taking the semiautomatic pistol and leaving the scene with it.

Georgia Department of Corrections records indicate Green was on parole after being convicted in 2018 of drug charges out of Muscogee County, and he was not allowed to have a gun.

He was taken to the Cobb County Adult Detention Center, where he was being held Tuesday.