The suspect attempted to grab Seiter's gun during the five-minute fight.
A woman passing by went to his rescue, helping fight off the attacker until other officers arrive.
Seiter got a chance to thank her in person.
"I do truly appreciate what you did, and my wife does, too," Seiter said.
"I did it because I felt like he needed a hand," said Angela Pierce, the Good Samaritan. "Everybody else just ran past."
Police don't recommend citizens jump into altercations like Pierce did, but Seiter said in this case, he's glad Pierce had his back.