The employee first believed the weapon to be an out-of-place toy but quickly realized it was real and loaded with live ammunition.
"I don't think someone would accidentally drop off a gun. I think he purposely left it there for a child to pick up and think, 'Oh it's a toy gun,' and accidentally point it at somebody and it goes off," one shopper told WMBF.
The police report mentions a suspicious male was seen browsing the toy aisles, and Target has said it will hand surveillance video of this shopper over to authorities.
"We take these matters very seriously and we are partnering with local law enforcement on this incident. Because this matter is under investigation, we are unable to share additional information," a spokeswoman for the retailer said in a statement to The Huffington Post.
The incident comes as the gun-control group Moms Demand Action for Gun Sense in America kicked off its national campaign calling on Target to prohibit the open-carry of firearms in its retail locations.
"Assault rifles and guns don't belong in the baby aisle, they don't belong in the toy aisle -- and they don't belong in any aisle of stores that American moms frequent like Target," the founder of Moms Demand Action, Shannon Watts, said in a statement. "It's time for Target, a store that American moms flock to, to follow the lead of Chipotle and Starbucks and prohibit the open carry of firearms."
The group's petition has placed Target in the middle of a debate between the gun-control group and a cohort of open-carry advocates known as Open Carry Texas, who have been in the news recently for bringing loaded assault weapons in to Chipotle, Chili's, and Sonic locations, prompting those restaurants to adopt no-firearm policies. They have sparked a national debate on open-carry laws that even elicited an apology from the NRA who publicly asked the group to "stop being weird."
Open Carry Texas has since backed off carrying in public amid intense criticism, but the incident at Target prompted the group's president, C.J. Grisham, to accuse Moms Demand Action of planting the weapon to further their cause.
"Target is currently in the crosshairs of gun control extremists who will stoop to [no] level too low to effectuate their agenda," Grisham wrote in an email. "Our children are our most precious commodity and intentionally putting them in any kind of danger to exploit a personal agenda is deranged, sick and twisted."
A spokeswoman for Moms Demand Action replied: "The insinuation that an organization devoted to the prevention of gun violence would plant a loaded gun in the toy aisle of Target is utterly ridiculous. Moms Demand Action is solely focused on the safety and security of our families and communities. Only one organization has a history of bringing loaded guns into Target -- it's not us."
Notable deaths of 2014 [PHOTOS]