LOS ANGELES (AP) - The assault-style rifle used by a Santa Monica gunman to kill five people last week appears to have been put together using component parts, according to two officials briefed on the investigation.
The officials, who spoke on condition of anonymity because of the ongoing investigation, said the semi-automatic weapon appears to have been built with parts that are legal to obtain, but put together make the rifle illegal in California.
The finding about the component parts was first reported by radio station KFI-AM.
Investigators found a drill press in 23-year-old John Zawahri's bedroom among other materials that indicate he likely assembled the weapon.
The drill press is used to help finish building the rifle by drilling holes in the lower receiver. A lower receiver that is only 80 percent complete can easily be purchased, and because it is not complete a person isn't required to go through a background check nor does it need to have a serial number.
In California such weapons require a "bullet button" kit, which needs to be added to a lower parts kit to make it legal. The bullet button kit modifies the weapon so that a separate tool must be used to release a magazine and reload it; without such a modification a person can press a button to release the magazine.