Off-duty guard stops shooting at Atlanta school

My big question is whether the off-duty guard was in uniform.  As an aside, this isn't the type of case that is in the news as the killer was only interested in killing one person, not trying to kill as many people as possible.

The armed resource officer who took the gun away was off-duty and at the school, but police didn’t release details on him or whether he is regularly at Price. Since 20 children and six adults were shot to death at Sandy Hook Elementary School in Connecticut in December, calls for armed officers in every school have resonated across the country. 

Hours after the Atlanta shooting, several school buses loaded with children pulled away from the school and stopped in front of a church about a half-block away. Parents tried boarding the buses. Police who initially tried to stop the parents, relented and screamed, "Let them off!" about the students. . . .