13-year-old allegedly threatened school shooting; had rifle, 100 rounds of ammo

A 13-year-old boy was taken into custody after allegedly threatening a shooting at a south Los Angeles middle school, authorities said Friday.

The alleged plot for a Friday shooting at Animo Mae Jemison Charter Middle School was thwarted on Thursday, Los Angeles County Sheriff Alex Villanueva said at a press conference.

A search warrant was obtained and investigators seized a rifle with a high-capacity magazine, about 100 rounds of ammunition, a list of students and staff, and a hand-drawn map of the school, authorities said.

Multiple students overheard the threat, Villanueva said, and teachers emailed the administration about their concerns. The administrators contacted deputies immediately, he said.

"The fact that people stepped forward" and reported what they heard allowed authorities to "prevent a possible tragedy today," said the sheriff.

The rifle is unregistered and investigators are working to determine its origin, Villanueva said.

There was initial confusion over the suspect having a "ghost rifle," which is assembled from gun parts and doesn't have a serial number, after tweets from Undersheriff Tim Murakami. The undersheriff later said the recovered "ghost rifle" was in reference to a separate incident.

The 13-year-old's gun "does have a serial number," Villanueva said at Friday's news conference. "This did not appear to be a ghost gun, no."

The suspect was taken into custody without further incident, authorities said. He was detained on a charge of criminal threats, authorities said. His name was not released.

This thwarted shooting comes one week after two students were shot and killed at Saugus High School, which is also in Los Angeles County. Three more students were shot and injured in the Nov. 14 attack, which was allegedly carried out by a classmate.