The child was killed on December 23 by an exploding grenade that ATF believes was bought on June 13 from the Fancy Flea Antique Mall in Shallotte, North Carolina.
CNN has reached out to the antique mall but has not heard back.
When the grenade was sold, the agency said the vendor and buyer didn’t believe the “grenades to be functioning or hazardous.”
ATF asks others who may have bought a grenade from the same shop to contact them, out of concern that the “grenades purchased from the vendor may contain live explosives and could be hazardous to the public.”
The volunteer who found it removed it from the building and law enforcement was called. No injuries were reported from the incident.