The Los Angeles Unified School District, the nation’s second largest, begins a new school year Thursday as it welcomes back more than 500,000 students. KTLA reporter Carlos Herrera spent

More than 4,000 people have been arrested across the region since June and it’s still unclear how the threat of detention may impact whether students show up to school and if they do, what type of support they might need.

After the school principal intervened, the agents left live bullets behind in a case of what the district superintendent called "mistaken identity."