WASHINGTON -- In August 2015, Eric McGinnis was arrested for violently attacking his girlfriend. A judge issued a protective order that said McGinnis could not own a gun for two years.
Less than a year later, the Dallas native tried to purchase a gun, but a background check by the gun shop thwarted his attempt. Then, according to the U.S. Attorney's Office for the Northern District of Texas, McGinnis obtained various gun parts and created the firing mechanism through 3D printing, giving him a fully functional homemade AR-15 assault rifle.
In July 2017, police arrested him as he was firing the gun in the woods. They also found a "hit list" of politicians, both Democrat and Republican, hidden in his backpack.
McGinnis was sentenced in February to eight years in prison for unlawful possession of a gun and ammunition.
The growing use of 3D printers and rising number of 3D gun blueprints posted to the Internet are likely to make such schemes more common, lawmakers and national security experts fear.
Sen. Bob Menendez, D-N.J., last month announced an effort to keep the Trump administration from transferring control of foreign arms sales from the State Department to the Commerce Department, a move he said would ease restrictions on the online distribution of 3D gun blueprints.
"These changes defy common sense, undermine public safety and undercut our national security," Menendez said in a statement.
Under the proposed change, the State Department would no longer regulate small arms exports, under which 3D gun blueprints are categorized, meaning its strict rules would not apply to the transfer of blueprints online. The Commerce Department's rules regarding the dissemination of such information are more lax.
Menendez introduced legislation to maintain State Department control over the blueprints and prohibit people from posting them online. He and the five co-sponsors of the bill, all Democrats, said their main concern is to keep homemade weapons out of the hands of criminals.
"We need to stop the spread of these firearms before they become a public health crisis," Sen. Ed Markey, D-Mass., said.
Increased access to 3D printers and weapons blueprints also could allow terrorist groups and foreign nations to begin printing their own guns and explosive devices, according to a report released by the RAND Corporation last May.
The report highlights how the growth of 3D printing, or additive manufacturing, has "the potential to dramatically disrupt the prevailing state system and international order."
But the RAND researchers caution that terrorists are not yet capable of building effective weapons, saying the cost of a 3D printer capable of producing a weapon would be prohibitive.
"There's got to be a lot of things that happen before 3D printing is more cost-effective," said J. Luke Irwin, assistant policy researcher at RAND and a co-author of the report.
Irwin predicted it would take at least a decade for terrorists to develop the capacity to print fully functional weapons because the technology is still unreliable.
Right now, Irwin said, "anything they make could be dangerous [for them] to use."
He also said hackers, whether terrorists, countries or criminals, could disrupt 3D printers to create flaws in their products.
"It's not unlikely," Irwin said, giving an example of someone inserting a flaw or change into the printing of an airplane part with potentially deadly consequences.
However, according to Mike Beltran, director of the 3D printing lab at Northwestern University, most industrial printers have procedures that would prevent someone from remotely printing a part.
"In order to actually print something, I need to hit a couple sequences of buttons right in front of the machine," he said. "None of these machines will allow me to just directly" print an object.
While lawmakers are working to restrict access to gun blueprints, Irwin said the government is unlikely to restrict access to the 3D printers themselves because it would stifle innovation. He suggested that a system be created to identify an attacker through his printer. Each printer would have a unique identification associated with the raw materials it uses so anything created by that printer could be traced back to it.
"It would be a stronger deterrence than keeping printers out of people's hands," Irwin said.