Stun guns have less voltage than police Tasers and you don't have to have a permit to carry them.
The suspect is 30-year-old Zachary McCabe. ABC7 News obtained a booking photo of him from another arrest in March. He was lying across two seats as the train pulled into the Pleasant Hill BART Station just before 9 a.m. When a 62-year-old man wanted to sit down an argument started.
"It turned from verbal to physical at some point and then patrons got involved to assist the victim," said BART Deputy Chief Ben Fairow.
BART rider Jeff Dunn was in the car next door wondering why it wasn't moving. He said, "Then somebody got off the car where apparently the problem was, got on our car and I heard her say something about, 'There's three guys holding him down.'"
"It appears as though the patrons that were assisting the victim in this case may have had Mr. McCabe in a headlock," said Fairow.
And they got him there with a woman's help when she used her stun gun on McCabe.
"Whether you're a police officer or an average citizen, you're allowed to use force to defend your own life," said Fairow.
"I laud the woman who used the stun gun on him. It sounds like it was the appropriate thing to do," said Dunn.
"It's nice to see that somebody stood up for somebody else," said BART rider Debbie Ross.
"I think that's great, that's community, that's BART ridership, that's people that are experienced on BART that react and don't just look away," said BART rider Wilson Tai.
The suspect is in jail in Martinez on battery charges.