Two males suspected of involvement in a Halloween shooting that wounded four people at the University of Southern California (USC) had been taken into custody, school officials announced Thursday morning. None of the suspects or wounded were USC students, according to Capt. David Carlisle of the USC Department of Public Safety. The four victims were rushed to hospitals after the shooting, which took place at Tutor Campus Center around 23:35 Wednesday, Carlisle said. One was listed in critical condition, while the others suffered no life-threatening injuries. The gunfire broke out at an on-campus Halloween party involving about 100 people, officials said. It stemmed from an argument between two men. One pulled out a handgun and shot the other and three bystanders, according to the school police. USC Department of Public Safety warned students to take shelter, remain indoors and stay away from the campus in a Trojans Alert issued after the incident. It also shut down the campus and cordoned off the shooting scene. The threat was declared over and the shutdown lifted around 2:15 a.m., according to a feed on the university\'s Twitter account. The entire campus was reopened at 4:52 a.m., according to a report filed by USC newspaper \"Daily Trojan.\" The school was only just recovering from a fatal shooting in April, which claimed the lives of two Chinese graduate students, who were shot while sitting in their parked car in a neighborhood off campus. Two suspects were arrested and charged in May. USC has since beefed up security.