reporter: from an early age, weldon mcdavid was passionate about protecting other people. i i used to protect my friends on the way home from school. we had a bully that tried and tried to start fights with us. and then i found out that a nicely applied arm lock would get that bully to kiss the street. and we didn t have to run from him anymore. reporter: when he grew up, weldon enlisted in the marine corps. after leaving the service, he worked as a firearms instructor. we met weldon back in 2013 when we covered the story of another woman he met at the shooting range. a customer walked in. and i could tell somethin was wrong with her. i i couldn t tell exactly what, but i i could read that she was under some kind of stress. reporter: her name was crystal harris. he s, like, yeah, can i help you. i said, i need to buy a gun. and i said, and it s not just for putting it away. i said, my life is in danger. and it s it s from my husband.