Corey Antwon Thompson, 45, was arrested in connection with the shooting death of 46-year-old U.S. Army veteran Roderick Butler, outside a Wells Fargo bank in Texas.
Thompson was out on bond from a previous arrest. Video footage showed him shooting Butler with an assault-style rifle.
He was tracked down after a woman reported a robbery attempt matching his description.
Butler, who had been homeless and had mental health issues, had recently moved to an apartment in Dallas.
His family expressed relief at the arrest.