Card, a firearms instructor and a longtime Army reservist, began to hear voices that were saying “horrible” things about him about a couple of months ago when he was fitted for high-powered hearing aids, according to Katie Card, who is married to his brother.

She said his mental health had deteriorated quickly.

“He was picking up voices that he had never heard,” she told NBC News. “His mind was twisting them around. He was humiliated by the things that he thought were being said.”