Ghost guns, a popular trend in the gun industry, is raising big concerns about safety.
Untraceable gun kits are sold right here in Tampa Bay and the I -Team found you don't need a background check or a license to make or sell one.
Last July on the streets of Baltimore, Dayten Harper shoots at police officers with an assault rifle. Officers fired back and killed Harper.
In California 3 years earlier John Zawahri uses an assault rifle on a shooting spree. Police say he killed his father and brother at home then fired dozens of shots at and around Santa Monica College killing 3.
What do both of these guns have in common? They had no serial numbers, no scratches, they were home made, and are untraceable. A shock to Baltimore's Police Commissioner Kevin Davis.
"When we found out that that gun was a homemade gun, I was on the scene and we're looking at it and we're all wondering what to call it, what do you think it is, and how do you describe it that was a big part of the conversation." says Commissioner Davis.
Law Enforcement call them Ghost Guns, or 80 percent guns, and they're becoming more popular.
"They can do it in the confines of their garage or home and nobody will know." says Assistant Special Agent in charge of ATF's Tampa Office Dave Brown.
Special Agent Brown says these homemade guns are becoming a huge problem for law enforcement.
"Our biggest concerns is we can't trace the guns... It's enough of a problem that I'm here today talking to you about it. The public needs to know we are seeing these guns unfortunately in the criminal element." Special Agent Brown says.
The I-Team found 80 percent gun parts are easy to find on the internet, they don't require a background check, and they're completely legal.
"Because an 80 percent theres no difference between this and a paper weight." says Mark Serbu with Serbu Firearms in Tampa.
Serbu explains the only part of an assault rifle required to have a registered serial number is the lower receiver.
But an 80 percent lower receiver isn't fully developed, therefore by law it's not considered a firearm.
"And what needs to be done is this pocket needs to be machined out as you can see and the holes need to be drilled the safety hole the hammer hole and trigger hole." Serbu demonstrates.
We found there are at least 6 manufacturers making 80 percent lower receivers in central Florida. They're sold in some local stores. You can even buy them online. The seller doesn't even need a dealers license because by law they are not considered guns.
We also found a template you can buy to make it easier to finish drilling out the holes needed to complete your kit. Video tutorials are all over YouTube.
"There's a pretty big market for them." Serbu says.
He can make 80 percent lowers but doesn't sell them. Serbu is in the process of getting government clearance to sell a homemade pistol kit.
"We're going to be putting a kit out so what we need to talk to ATF and send them something to say hey do you consider this kit to be a gun or not a gun?"
Law enforcement we spoke with say these untraceable gun parts appear to be a loophole in the law and fear it makes it easier for people who fail criminal background checks to build one.
"That concerns us and we don't see that often in Baltimore but the fact that we saw one concerns us greatly." Says Baltimore Police Commissioner Davis.
ATF Special Agent Dave Brown says he's personally seized a fully automatic homemade gun.
California passed a law requiring all homemade guns be registered, regardless of what federal law states.
Hobbyists who build homemade guns tell us a new law isn't going to stop shootings from happening and that criminals won't take the time to build a homemade gun, they will just steal one and scratch off the serial numbers.
Investigator Jarrod Holbrook is an Emmy and AP Award winning journalist. If you have a tip email Jarrod Holbrook at firstname.lastname@example.org. You can follow him on Twitter @jarrodholbrook and Facebook.