"It was a fight that escalated and got out of control," Cobb County Fire Department spokeswoman Denell Boyd said.
Ben Pinto, whose brother Jack was among those killed in the 2012 elementary school shooting, played linebacker for Newtown.
Excavation of the site in San Antonio, Texas, where the bodies were found was halted.
The children, ages 3, 6 and 9, were left in a mini-bus which contained a propane tank and a five-gallon bucket meant to be used as a makeshift toilet.
The transit authorities in Los Angeles, Philadelphia and Chicago have taken action after an investigation on mica mining in Madagascar.