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KANSAS CITY, Mo. -- While we go about our days, there's a mighty force that operates under the radar, without recognition, to keep us safe.

The most dangerous job in law enforcement? Hunting down shooters, murders and armed robbers -- the most dangerous criminals in the metro.

"When everything is Game 7, there is no Game 8. Everything is going to be decided today," said Eric Immesberger, the ATF resident agent in charge of the gun squad. "And that is the mental focus that we approach what ever we do every day."

There are no do-overs and no second chances. Lives are on the line. Every day is Game 7 for Kansas City's Group 5 Gun Squad.

"Who do I work for? I work for the 20-year-old gal that is pushing the stroller down Troost Avenue. I work for the 12-year-old kid who is stuck in a violent neighborhood and has this mayhem going around him, and he has no options," Immesberger said. "Those are the people we work for. We fight for those who can`t fight for themselves."

The Group 5 Gun Squad is an elite group of law enforcement officers made up of KCPD officers and ATF agents.

It was his squad that hunted down murder suspect Marlin Mack, wanted for shooting and killing UMKC student Sharath Koppu during a robbery attempt in July.

Nine days later, Mack was spotted at the Sky-Vue Motel on 40 Highway.

"During surveillance, one of my partners was in an undercover capacity, and we positively identified it was him," said a squad member who FOX4 cannot identify. "At that point we went into enforcement mode to arrest him."

When the gun squad tried to arrest him, Mack opened fire with an AK-47 pistol. Two officers were shot. Mack took off, and the squad chased him to 29th and Topping.

"We had several eye witnesses with him running across the highway with a rifle. It was the same one, which was at the previous scene where he had shot the other officers."

The chase came to an end at an abandoned house in the 29th and Topping. That's where a third officer was shot.

"As officers were beginning to make their approach, he came from the second story window and began shooting," the agent said. "And the second portion of the gun battle began."

Mack was killed in that gun battle.

"When it ultimately comes down to an arrest, the bad man will vote how that is going to go," XXX said. "The vast majority are presented with an overwhelming force, and they surrender. Marlin Mack chose to not surrender."

Another suspect who chose not to surrender was Jason Simon. During a stolen auto investigation, Simon pointed a shotgun at a Missouri State Highway Patrol trooper. The gun squad went after him.

Immesberger and his crew lured Simon to the Crossland Economy Suites in Independence.

"I observed him get out of the vehicle holding a shotgun and walking up to the hotel," said a squad member who FOX4 cannot identify for safety. "As bad luck would have it, that particular part of the city has dead spots on the radio, and we were not able to properly communicate. That individual was able to make it up to the second level of the hotel."

With Simon on the second floor of the hotel, agents scattered to make sure he didn't get into a room and didn't escape. Unable to communicate, the gun squad had to rely on training and instinct.

"Once all of my squad was on the second level, we announced the presence of law enforcement and ordered him to drop the weapon," the agent said. "He refused. He continued to run through the outer perimeter of the second floor of the hotel, at which point we heard two gunshots."

"Unbeknownst to us, two of our other squad members were on the opposite side and had fired multiple shots at him," the agent continued. "At that time, the individual had ran back around and started to charge us, at which point he was shot."

Simon fell to the ground, and then the officers who just shot him tried to save him.

"You got a duty and an obligation to help save that life," the agent said.

Simon is now in federal custody on gun and drug charges.

Immesberger's gun squad has arrested more than 100 of the most violent people in Kansas City.

But it's not always a one-squad job. They often partner with an undercover squad, the street narcotics tactical officers, the gang unit task force and the career criminal task force.

"Anybody's mission that comes down the pike, we deploy and we can handle any mission that comes down," Harold Lett said.

Lett is the ATF senior special agent assigned to the career criminal unit. He said the men who make up these units are some of the most extraordinary agents he has worked with in his 26 years in law enforcement. '

"The reason that things work seamlessly and so well here in Kansas City among the federal agencies, the police department, everybody is three simple things: trust, relationships and no ego," Lett said. "I don`t care whose handcuffs go on the bad man as long as the bad man is removed from society and the bad man is not going to hurt anybody else."

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