(Adds police testing gun, details)
By Dan Whitcomb
LOS ANGELES, April 18 (Reuters) - Four students were robbed at gunpoint near the University of Southern California on Wednesday, and investigators were testing the weapon in that case to see if it was the same one used to murder two graduate students from China last week, police said.
A man brandishing a handgun confronted the three men and a woman as they walked near USC's fraternity row after midnight, demanding property from them, Los Angeles police officer Sara Faden said.
The students handed over the belongings, but then two of the men chased the gunman, she said.
"At that time, apparently the victims were able to flag down a public safety officer from the USC campus police and the officer went in pursuit," she said. Police later shot and wounded the suspected gunman.
The incident came after the slayings of two Chinese graduate students last week sent shockwaves through USC, a private university that boasts the largest number of international students of any American institution of higher education.
The murders also sparked a debate over whether the school provided adequate security measures in neighborhoods adjacent to the Los Angeles campus where many students live. Police and university officials say violent crime in the area has diminished in recent years.
Investigators had not determined if Wednesday's robbery was related to the shooting deaths of Ming Qu and Ying Wu, both 23, who were killed in a residential neighborhood near the school, police said. But police were conducting ballistics tests to establish whether the same gun was used in both crimes.
Detectives "are going to turn this case upside down and see if it leads to something," Lieutenant Andy Neiman said. "Whether this is the guy or this is the gun, or this guy has an associate" who may be involved.
He said investigators would also study tapes from nearby surveillance cameras.
In last week's murders, evidence suggested that Qu and Wu, who were apparently involved in a budding relationship, were gunned down by a single assailant who approached their car, a 2003 BMW, as the victims sat talking inside at about 1 a.m. last Wednesday.
Wu was found slumped over in the passenger seat, reportedly shot in the chest. Qu, said by local media accounts to have been struck in the head, staggered out of the car to the porch of a nearby home, where he collapsed.
A witness reported seeing a person in dark clothing running from the scene, and a black sedan was observed pulling away from the area at about the same time, police have said.
Police also said that some unspecified property of the victims was taken, suggesting robbery might have been a factor. But detectives stressed they have yet to rule anything out in terms of a motive, including whether street gangs were involved.
Police have posted a $125,000 reward, to be paid by USC, for information that would help solve the case. (Reporting by Dan Whitcomb; editing by Cynthia Johnston and Mohammad Zargham)