PAUL: Police in Los Angeles say they've thwarted a potential mass shooting this week. Thanks to a tip from students.</s>BLACKWELL: Authorities arrested a 13-year-old boy, and they found a weapon, ammo, body armor, and a list of names on what the police called a hit list. Here is CNN's Nick Watt.</s>NICK WATT, CNN CORRESPONDENT: A 13-year-old student at this L.A. middle school was arrested Thursday. We're told he'd planned the shooting for Friday.</s>ALEX VILLANUEVA, SHERIFF, LOS ANGELES COUNTY: Students that the suspect made the threat to report it to the school administration, and they, in turn, reported it to us.</s>WATT: His home was searched.</s>VILLANUEVA: A rifle with a high-capacity magazine was seized along with ammunition for the rifle. And that is the rifle that was seized.</s>WATT: Along with around 100 rounds of ammunition.</s>VILLANUEVA: The subject also had in his position a rudimentary hand- drawn map of the school, as well as a list containing names of both students and staff members from the school.</s>WATT: And here in South L.A., see something, say something might just have saved a lot of lives.</s>VILLANUEVA: The fact that people step forward and said what they -- what they had heard, led to us to be able to prevent a tragedy today. So, definitely, kudos to the staff and students of this school.</s>WATT: That 13-year-old is now in custody along with an adult relative as the investigation continues. One focus is that weapon that was seized, a semi-automatic A.R.-15 rifle that was unregistered. Authorities want to find out who owned it and how they got a hold of it. Nick Watt, CNN, Los Angeles.</s>BLACKWELL: The next hour of your NEW DAY, starts after a quick break.
Middle School Shooting Thwarted By Police.