LOS ANGELES - Los Angeles County District Attorney Steve Cooley told Chinese reporters here Friday that if the two defendants charged with murdering two Chinese students at University of Southern California were convicted, they face death penalty or life without parole.

However, Cooley said prosecutors will have to wait till after the preliminary hearing to ask formally for the death penalty.

On April 11, graduate students Ming Qu and Ying Wu from China were shot while sitting in a BMW about a mile away from the University of Southern California. Both victims were 23 years old.

Javier Bolden, 19, and Bryan Barnes, 20, were arrested in May on suspicion of killing the students during an apparent robbery attempt.

However, almost two months after their arrest, the two defendants have not even been arraigned, and it is said that they would only receive a penalty of 20 years in jail even when they were convicted.

That has angered students at the University of Southern California and the Chinese community in the United States.

There are about 38,000 students attending the University of Southern California from foreign countries, 2,500 are from China. The school has more international students than any other U.S. universities, according to the school authority.

Safety issue has concerned the Chinese community as well as many parents in China after the shooting took place.

Chinese students at the University of Southern California started a campaign to gather signatures for a petition to urge the prosecutors to prosecute the killers to the full extent and protect the safety of the Chinese students.

In over a month, about 7,000 signatures have been collected. Howard Wang, president of South West Chinese Students and Scholars Association, handed the petition to the Los Angeles County District Attorney' s Office Friday and asked the office to convey the concerns and demands to the prosecutors and the judges.

Cooley said that his office has assigned the best prosecutors to cooperate with the police officers to prosecute the defendants to the full extent.

He said he fully understands the concerns of the Chinese students here in the United States and their parents in China and will make full efforts to prosecute the defendants.

However he said the process will take about one year, that' s because the U.S. judicial system is complicated and the defendants have the right to defend themselves.

Till now the motive for the shootings of the two Chinese students was still under investigation, according to the police, but the evidence points to a street robbery.

Ballistics tests on shell casings recovered at the scene show they were fired from the same gun used in two other shootings in Los Angeles, according to law enforcement sources.

One of the suspects took a cellphone from one of the victims and detectives were able to locate him by tracking signals sent by the device, according to the police.

Authorities also identified a signal from a second cellphone in proximity to the victim's phone. The second phone was identified as belonging to the suspect.