A trial is underway in the case of two Milwaukee police officers who were wounded in the line of duty and are now suing the gun store who sold the firearm.

The officers alleged that Badger Guns “negligently and unlawfully sold” the handgun that was used in the shooting.

Officers Bryan Norberg and Graham Kunisch were shot in the face in 2009. Both officers suffered devastating injuries.

The civil suit could set a gun law precedent if they win.

The 18-year-old gunman, Julius Burton, had a history of mental illness and is now serving an 80-year prison sentence.

Security footage from the store shows Burton entering the store with a "straw buyer," who was allegedly paid $40 to purchase the firearm for Burton.

Judge Andrew Napolitano explained on "The Real Story" that these cases are not common, because typically police and other service workers harmed in the line of duty will accept guaranteed income from workers compensation insurance.

In this case, Napolitano said the claimants are "rolling the dice" because they may not win as much from the gun shop’s insurance.

He said the officers must prove that the gun shop owner was negligent in not aggressively enforcing the background check and failing to scrutinize whether he would pass that gun to somebody else.

Napolitano concluded that the officers have a case, because there were “triggers” that should have tipped off the gun shop owner.

Get more insight from Judge Napolitano in the video above.

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