LOS ANGELES (AP) — Los Angeles police are looking for at least three suspects in the off-campus death of a USC graduate student from China.

Police say an acquaintance found the 24-year-old engineering student Thursday morning on the fourth floor of an apartment building.

The university says he died of a head injury. His name wasn't released.

Police Lt. Andy Neiman says at least three people assaulted the student but the motive is unclear and it doesn't appear he knew the attackers.

Neiman says the student was on his way home after attending a study group and walking home a friend.

In 2012, two Chinese graduate students were shot in a car during a robbery near campus. One of two men charged with the killings has pleaded guilty to murder.