Officers responded to a welfare check/CIT. Upon arrival, officers met with reportee, who stated the suspect is his brother. Reportee advised the suspect had been having issues with drinking and using drugs. The reportee also informed officers that the suspect was threatening him and the neighbors. Officers made contact with the suspect who became aggressive toward the officers. The suspect then went into the residence while threatening to assault his brother, the neighbors, and the officers. The suspect threatened to retrieve a pistol and shoot the officers. At that time officers discharged their C.E.D. (tasers) at the suspect twice, with no effect. After making the threat, the suspect moved hastily toward the kitchen behind a counter that obstructed the officers view of his hands. The officer, in fear for his life and the life of his partner, discharged his firearm at the suspect, striking him multiple times. First aid was administered; however, the suspect succumbed to his injuries.