LOS ANGELES, Jan. 15 -- Los Angeles Superior Court Judge M.L. Villar decided Thursday to require three of four defendants in the case of murder of a Chinese student at the University of Southern California (USC)to proceed to trial on a murder charge after a three-day hearing.

Villar said she found "overwhelming" evidence to require Jonathan Del Carmen, 19, Alberto Ochoa, 17, and Alejandra Guerrero, 16, to proceed to trial on the murder charge stemming from the robbery-motivated July 24 attack on Xinran Ji, a 24-year-old electrical engineering graduate student in the USC, who was beaten to death on that day while walking back to his apartment.

A fourth defendant, Andrew Garcia, 19, is also charged with Ji's murder. Criminal proceedings against him were suspended Tuesday pending an evaluation next month to determine if he is mentally competent to stand trial.

Along with murder, all four defendants face a special circumstance allegation that the murder occurred during an attempted robbery. The Los Angeles County District Attorney's Office will decide later whether to seek the death penalty against Del Carmen and Garcia. Ochoa and Guerrero cannot face the death penalty because they are under 18.

Ji was attacked after walking a woman home from a study group on July 24, 2014. He managed to make it back to his apartment, where he was found lifeless in his bed by one of his roommates.

In testimony Wednesday, Detective Paul Shearholdt from the Los Angeles Police Department (LAPD) said that Del Carmen, Ochoa, Guerrero and Garcia gave varying accounts about the attack on Ji while being interviewed one-by-one at the LAPD's 77th Street Division. But all the four acknowledged in police interviews that there had been discussions in the car about "flocking" or robbing people, the detective testified.

Garcia told investigators that the man was targeted because he was Chinese and is presumed to have cash, said Shearholdt.

Ji died from severe cranial cerebral trauma, said Dr. Louis Pena, who performed the autopsy for the Los Angeles County coroner's office. Ji also had a broken nose and bruising on his arms and one of his hands, and some of the injuries were consistent with defensive wounds, the deputy medical examiner testified.

Pena said Ji's wounds were "pretty severe." Even if he had been taken to the hospital, he probably would have died within hours or days.