An armed veteran from St. Louis killed one man and injured another during an armed robbery attempt in the metro east.

But, on Friday, prosecutors said the veteran's actions are justified, and could help solve dozens of other violent crimes in Illinois and Missouri.

Madison County State's Attorney Tom Gibbons said this case should serve as a warning to criminals. If you're coming to the Metro East to break the law, you could end up staring down the barrel of a gun.

Thursday morning, Venice police were called to the 200-block of Abbott Street for reports of a shooting. Madison County State's Attorney Tom Gibbons said it happened as a 70-year-old Vietnam Veteran from St. Louis was dropping off his friend.

"Two individuals rolled up next to them in a vehicle, asked for directions, and when they had their attention, took out a firearm," Gibbons said.

Gibbons said the veteran responded by opening fire with a concealed weapon, killing one suspect — 19-year-old Billy Dickerson — and injuring the other — 23-year-old Perry Richardson.

"He feared for his own life,” Gibbons said. “He feared for the life of his friend and just took decisive action in that moment."

Gibbons said both suspects were wanted for other violent crimes across the bi-state that could now see some closure.

"We're able to probably, I believe, able to solve possibly dozens of other armed robberies in the area."

As for the veteran, Gibbons said he was well within his rights.

"This is an example of a law-abiding citizen protecting himself, exercising his right to self-defense." 33:35

But as for Richardson, he's now charged in the death of the other would be robber.

"If you're engaged in a forceable felony and someone — no matter who — dies during the course of your crime, you are accountable for murder."