Caught on video: Jiujitsu instructor steps in, pins down suspected thief at Ravenswood convenience store

CHICAGO (CBS) -- Video shows a Good Samaritan stepping in to help a store clerk during an attack on the city's North Side last week.

As CBS 2's Jermont Terry reported Monday night, what the attacker didn't know was that the Good Samaritan also happens to be a jiujitsu trainer.

The Supreme Jiu-Jitsu Academy is located on Lincoln Avenue just northwest of the intersection with Halsted Street and Fullerton Avenue. Owner Idriz Redzovic enjoys teaching the art of self-defense to youngsters there.

But last week, while at a 7-Eleven at 1532 W. Lawrence Ave., just east of Ashland Avenue in the Ravenswood community, Redzovic needed to press those skills into action for real.

"I came inside here and took him to the ground," Redzovic said.

Surveillance video shows a man punching an employee – and within a flash, Redzovic jumps in.

Redzovic said the trouble started well before the man punched the worker.

"This female walked in complaining about an individual outside harassing them," he said.

At 10:15 p.m. Thursday, June 16, police said the suspected thief entered the 7-Eleven and proceeded to take food items and try to walk off without paying. The 19-year-old store clerk did not approach the thief at the time, police said.

But the same man entered the 7-Eleven again soon afterward and was asked to leave – at which point he punched the clerk, police said.

Soon afterward, Redzovic had him in a jiujitsu "gift hold."

"Hey homie, let me go," the man is heard saying.

"No," Redzovic tells him. "You swung at those dudes."

The suspected thief quickly discovered the power of a third-degree blackbelt. Four days after the incident, Redzovic showed us how the take and hold work.

"I controlled, and I wrapped up his hands - so I'm safe and he's safe," Redzovic explained.

Using the hold, Redzovic detained the man – but never cut off his airways. The suspected thief is even heard speaking in the video.

"I wasn't sitting on him," Redzovic said. "I put my foot up, and if you notice, there's no weight on him."

So why did Redzovic choose to get involved?

"I feel like it's my duty as a human on this plant to help another human in danger," he said. "It could've gone two ways. The employee could have took him down also and pounded his face and beat him up."

Despite the rapid takedown and hold, Redzovic never injured or hurt the man. He stayed holding onto the suspected thief until police arrived 13 minutes later.

And with so many people making split-second decisions with weapons, Redzovic had a warning.

"You don't pull out your gun unless you think the guy's going to pull the trigger – unless your life is in danger," he said.

Christopher Cruz, 30, was arrested and charged with one misdemeanor count each of battery and retail theft. Redzovic hopes the suspected thief learned something too.

"If he sees this, this could be a wake-up call for the man to change his life around," he said.