The teenager who gunned down two classmates at a California school last week before shooting himself used a “kit gun” that is untraceable, authorities said Thursday.

In a tweet, Los Angeles County Sheriff Alex Villanueva said the so-called “ghost gun” used by Nathaniel Berhow was assembled from parts that do not have serial numbers.
He said kit guns -- also known as “80 percent guns” - are sold at gun shows or can be purchased online, allowing owners to skirt California’s gun laws.
Ghost guns “are sold as a kit, and you can legally buy it, assemble the weapon yourself and you have a gun that is not registered and no one knows that you have it, it’s very dangerous,” Villanueva told ABC7.
The sheriff added in a statement that it was unclear who assembled the .45-caliber pistol used by Berhow last Thursday during his rampage at Saugus High School, a short commute from Los Angeles.
Two fellow students were killed and several others were injured before Berhow, who had turned 16 that day, shot himself in the head. He died a day later.
Authorities are still trying to piece together what prompted the shooting, especially as Berhow had no history of troubled behaviour.
{{/usCountry}}Authorities are still trying to piece together what prompted the shooting, especially as Berhow had no history of troubled behaviour.
{{/usCountry}}Villanueva said Berhow’s father had six registered guns that were lawfully removed from the home and subsequently destroyed. A later search turned up the “kit gun.” The sheriff said investigators are looking at Berhow’s electronic communication in the hope it will shed light on his motive.