I see a man beating a woman. I have a gun. What should I do?

“The man with the gun told police that he had seen the other man assaulting a female passenger. When both vehicles stopped, the man with the gun got out and pointed it at the other man and held him there for police, the release said.

“Traffic on Farm Road 1709 stopped in both directions until officers arrived, the release said.

“The man with the gun, who was not identified by authorities, has a permit to carry a concealed handgun, the release said.”

http://donsurber.blogspot.com/2014/12/citizens-arrest-texas-style.html