Neon Tommy reports that the shooting occurred just after 11:30 pm outside the Ronald Tutor Campus Center, where a Halloween concert was being hosted. The event was reportedly at capacity, and a crowd of over 100 people, including campus police, was outside the venue when at least four shots rang out.
The shooter opened fire on one victim, who was critically wounded, but also hit three bystanders who sustained non-life-threatening wounds. L.A. Times reports that neither the gunman nor any of the victims were USC students, and that the shooting was over a dispute unrelated to the university.
The campus went into immediate lock down while police searched for the gunman, and remained on complete lockdown until around 4 am according to the USC's twitter account. Two suspects have been detained, and the university reports that no others are at large. The LAPD is concluding their investigation of the incident, and the campus is back to business as usual.