Don Ashley filed suit asking the Office of the Inspector General to review whether any state laws were violated.
He seeks damages including back pay, compensatory pay and reinstatement.
DA Charles Scott says the firing had nothing to do with the gun sale or Ashley’s disclosure of it.
Ashley had been with the DA’s Office 17 years before the firing and was a Shreveport police officer for 21 years prior to that.
Scott’s office received M16 rifles through the La. Federal Property Assistance Agency.
A spokesman for Scott said the guns were needed to provide another layer of protection to ADAs and district attorney investigators, who often must work in dangerous neighborhoods and with potentially dangerous witnesses.