LAPD Officer Sarah Faden says one victim remains hospitalized in critical condition. None of those involved are USC students.
She also says a weapon was recovered near the shooting scene outside a Halloween party but investigators will have to test it to determine if it was the one used in the attack.
Students were told to shelter in place with a campus-wide alert issued minutes after the 11:30 p.m. shooting Wednesday. It was lifted three hours later and students were advised classes would be held as scheduled Thursday.
An argument between party crashers outside a Halloween bash at the University of Southern California late Wednesday ended with a shooting that critically injured one man, wounded three and triggered a campus-wide phone-email-text alert for students to shelter in place.
About 10 minutes after the 11:30 p.m. shooting outside the Ronald Tudor Campus Center, two men were arrested by campus police and turned over to Los Angeles police.
Two men were arguing when one of them pulled a gun and opened fire, said USC police Capt. David Carlisle. One man was shot several times and critically wounded and three bystanders were wounded with non-life threatening injuries, he said.
None of those shot or arrested were USC students, the captain added.
The student alert was lifted about three hours later and students were advised a normal class schedule was planned Thursday.
Carlisle said about 100 people attended the student-only party, sponsored by a student group. Dozens more were outside.
"This is the first violent crime we've had on campus this year," Carlisle said.
In April, two USC graduate students from China were shot to death in a car about a mile from campus. Police believe Ming Qu and Ying Wu were victims of an apparent robbery.
Two men have pleaded not guilty to murder charges in the case. Trials are pending.
In other Halloween violence in Los Angeles, three people were shot around 10 p.m. on Hollywood Boulevard near the Halloween parade and party that annually draws hundreds of thousands of people.
Despite a quick police response by officers in riot gear, on horseback and bicycle who were on duty for the Halloween revelry, the gunmen got away.
Police said a 17-year-old boy was critically wounded with gunshot wounds to the chest and a leg. A 14-year-old boy was shot in the foot and a 25-year-old man was struck in the buttocks.
(Copyright 2012 by The Associated Press. All Rights Reserved.)