That's not what the story said. It says that he observed the man, who fit the description of the rapist/woman beater (long haired red headed men being a not all that common, except in certain circles) running into a nearby house, probably around the corner by the address and location given. He didn't know if the man lived there or not and he didn't know who the red headed stranger was. He then observed the man exiting the house and moving away. He asked him to stop and wait for the police. He did not pull his weapon until the man began fumbling in his pockets for something, which indeed turned out to be a pistol.
So the only thing that might constitute "overstepping his bounds" was trying not let the thug who beats up on women get away, by observing him, and asking him to wait for the police to arrive. The thug is the one who went for his gun first, although he botched it pretty badly, and won't be beating up any more women. His girlfriend *probably* will be beaten again, as most women who pick one violent loser will likely pick another one. But lets pray she doesn't.
Sounds as if the "stranger" wasn't quite a stranger after all. I'm sure that the DA will want to know what type of "interactions" these two had previously.
She said she saw the man run into the house at 2020 W. 13th Ave.
He did not say that he observed the man do anything other than look out a window which he interpreted as suspicious behavior.