CHICAGO (WLS) -- A simple, cheap metal switch attached to guns can quickly turn them into illegal automatic weapons. The devices, known as gun switches, are a new and dangerous threat for police and the public.
"So very scary and dangerous. Those automatic weapons could potentially take us out," said Aurora police officer William Whitfield.
Last July, Whitfield helped apprehend a suspect after finding what he describes as a homemade handgun illegally switched to full auto-fire.
"We were able to get that gun off the street. It's still a wow moment, like wow people are really doing this now," he said.
When pistols are turned into fully automatic weapons they rapid fire bullets as long as the trigger is pulled, essentially creating a machine gun with the installation of a metal switch. They are dangerous in the hands of criminals, and entirely illegal for almost everyone.
In October in Aurora, a chase following an attempted traffic stop produced what police said was an illegal gun altered to fire full auto. That gun was pulled from a suspect's backpack.
Just a couple months earlier in Aurora, police said one of three men in a moving car opened fire near a funeral home with an automatic weapon. That pistol had been illegally converted to full auto with a switch that authorities say is advertised on the internet and easily bought by mail.
Lieutenant Greg Spayth, with the Special Operations Unit of the Aurora Police Department, said the increasing fire power is definitely becoming more dangerous.
A former member of the ATF federal gun task force, Spayth said the danger is significant for police and also the public.
"We're not talking about people who have been trained to use firearms," he said. "Often times they are gang members, so you put a fully automatic handgun into the hands of a 13-, 14-, 15-year-old kid. And those rounds are spraying everywhere."
Earlier this summer, motorists at a South Side intersection witnessed shooters with automatic weapons opening fire. On that day, passersby avoided the spray of bullets and were not harmed.
But that wasn't the case on in Chicago's Fulton River District on Sept. 29, when five people were wounded in a high-speed, car-to-car firefight with apparent automatic weapons.
"I don't know that anyone has their arms fully around the extent of the problem," said John Lausch, U.S. Attorney for the Northern District of Illinois. "What we're seeing is offenders who are completely emboldened. They're using guns to shoot people, commit carjackings, and they're doing it at all hours of the day, and really all over the city. "
Lausch said the guns are a huge threat, and suspects who are caught with the altered weapons can face machine gun charges.
"And so we work with ATF in the Chicago Police Department to charge exactly those cases. And that is something of a trend that we've seen in the last couple of years," he explained.
In Aurora, another trend has police concerned: too often, after seizing large arsenals from occupied vehicles, police find there is not enough proof of which person inside actually had possession of the weapons to file charges.
"You clearly want them to be arrested and charged and oftentimes, that's just not the case anymore," Spayth said. "And so it's sometimes a little defeating for the police when you have to walk those people out the door and let them go."
Police told the I-Team they try to circle back and make arrests if they find sufficient evidence. And even as federal authorities work to take on more local gun cases, they stressed that state penalties for felony possession of a firearm are generally more serious than federal penalties.