Authorities said a 15-year-old was charged Thursday in the shooting death of a longtime National Guardsman.

According to The Tennessean, Christopher C. Farrar has been charged with one count of criminal homicide for the deadly shooting that occurred Wednesday at a National Guard armory in Tennessee.

The teenager is accused of gaining access to the armory around 5 p.m. and opening fire on Sgt. 1st Class Michael W. Braden.

"This is a sad day for the Tennessee National Guard," Maj. Gen. Max Haston, the adjutant general of Tennessee, said in a statement. "We have tragically lost one of our own. Our hearts and prayers go out to Sgt. 1st Class Braden's wife and children, his extended family and to our Tennessee National Guard family."

The Associated Press noted that Tennessee Bureau of Investigation spokesman Josh DeVine said the building does not have surveillance cameras, but at least one other person was in the armory with Braden. However, DeVine said it is unclear at this time if they actually witnessed the shooting.

Police did not yet announce what the suspect’s motive could have been and are still investigating the incident.

The teen is being held without bail.