LOS ANGELES (AFP) - A US man convicted of murdering two Chinese students during a botched robbery was on Monday jailed for life without the possibility of parole for his role in the killings.

Javier Bolden, 22, was found guilty last month of shooting dead Wu Ying and her boyfriend Qu Ming as the couple sat in a car outside the downtown Los Angeles campus of the University of Southern California.

An accomplice, Bryan Barnes, had already pleaded guilty to the crime and was given life without parole in February.

Sentencing Bolden on Monday, Judge Stephen A. Marcus said the murders had "stained the reputation of Los Angeles".

Marcus said Bolden had shown "no remorse" during the trial, and at one stage held up a copy of the Los Angeles Times newspaper which showed the killer smiling in court.

"You are not repentant," Marcus said, describing it as "truly one of the saddest cases that I've had to preside over."

The father of Qu Ming on Monday described Bolden and Barnes as "two extremely evil specimens of human trash".

Qu Wanzhi, who had requested the death penalty for his son's killer, also criticised the sentence as too lenient.

"This judgment is ... unfair to our children and of little comfort to their souls in heaven," Qu said, adding that the sentence was "humiliating to the people of China as well".

During the trial, prosecutors told how the 23-year-old graduate students were "helpless victims" inside a parked BMW and that Bolden and Barnes "counted down the seconds" as they approached the car before opening fire.

Barnes and Bolden were arrested in May 2012 after being traced by the dead students' stolen cell phones.