Additional charges have been filed against the two South Pasadena High School students arrested last month in connection with a plot to kill staff members and students on the campus, the Los Angeles County District Attorney’s office said Monday.
The two boys, aged 16 and 17, were each charged with conspiracy to commit murder and conspiracy to commit assault with a deadly weapon.
Spokesman Greg Risling said the boys, who have not been publicly identified because of their age, both denied the charges in court Monday.
The denials are the juvenile court equivalent of pleading not guilty.
Both boys are due back in court Sept. 23.
Prosecutors say the teens began making detailed arrangements to kill three staff members at South Pasadena High School and gun down as many students as possible.
The pair told another student about the mass shooting plan and they threatened to kill him, according to the District Attorney’s Office.
They were initially charged only with one count each of making criminal threats in connection with their interaction with the third boy as the investigation into the school plot continued.
The plan was thwarted when the boys were arrested Aug. 18 following a police investigation into the alleged plot.
South Pasadena Police Chief Art Miller said at the time of their arrest that the threat the two posed was credible.
"It was very viable, what they were plotting," Miller said. "They were making a huge plan of a school massacre."