Bryan Barnes, 21, pleaded guilty to two counts of first-degree murder for killing Ying Wu and Ming Qu as the victims sat in a car near the USC campus in April 2012.
In exchange for the guilty plea, prosecutors said they agreed to allow Barnes to serve two consecutive life sentences in prison, the Los Angeles Times reported.
Prosecutors said during a hearing in the case in 2013 investigators tracked Barnes and a second suspect, Javier Bolden, 20, using an iPhone that was taken from Wu. They said they obtained a court order to monitor Barnes' phone conversations and heard him at one point discussing the shooting with Bolden, who has yet to be tried in the case.
A transcript of the call indicates Barnes had intended to unlock the phone and give it to Bolden for his birthday. Instead, he sold it to a mobile phone shop for $230, the Times said, citing a transcript of the call between Barnes and Bolden.
Bolden's attorneys have argued there is insufficient evidence to connect him to the slayings, but the judge in the case noted Bolden shows no surprise at what Barnes says about the crime.
A former girlfriend of Barnes has testified he admitted stealing the phone and told her he "might've shot somebody."
Prosecutors said evidence from the scene of the students' killing connected Barnes and Bolden to at least two other shootings.