Determan knows his way around a boxing ring. Growing up in Omaha, he stayed in his father's gym, moving to North Texas two years ago with a 5-and-0 pro record.
"Came down here to basically get better training, better sparring," he said. "In the Midwest, there was not too much for me, so that's when I hooked up with JB."
JB Hurd is Determan's trainer.
"I get an email that says, ‘Hey, we're moving down there, we'd like for you to train me,' and all this," said Hurd.
Determan was in the gym and in class at Southwest Assemblies of God University when his childhood dream came true.
"I represent all the men and women in blue," said Determan.
The police officer's fighting name is Johnny "The Law."
"We got his application and we started researching him he went through our processes and he was a gem," said Chief Garland Wolf with the Red Oak Police Department. "…He's somebody that.embodies absolutely everything we're looking for in a law enforcement officer and I think the qualities that he brings into the ring are the same qualities that we look for on the street."
Since moving to North Texas, Determan is undefeated in four fights, knocking out all comers. Saturday night, he's on the undercard of HBO boxing.
"Not all police officers are bad," said Determan. "You know, all the stuff going around on the internet and media and stuff…everybody's against police officers. They're…all they're seeing is that small two or three percent having a bad day or whatever. Not all cops are like that."