A 13-year-old Los Angeles student was arrested after he allegedly threatened to shoot up his middle school. In a news conference Friday, the Los Angeles Sheriff's Department said they began investigating the matter after receiving a report of the threat against Ánimo Mae Jemison Charter Middle School on Thursday. Students had heard that a shooting would take place on Friday, and police were notified of the students’ concerns. Interviews led police to believe a 13-year-old male was the suspect, and a subsequent search of his home concluded in the seizure of a high-capacity assault-style rifle, about 100 rounds of ammunition, a drawing of the school’s layout, and a list of names of students and staff. Police said the teen was taken into custody without incident, and the investigation is still ongoing.