USC students on their way to attend a memorial service on April 18, 2012 in Los Angeles, California, for the two Chinese graduate students who were shot to death near campus last week. US authorities have offered $200,000 in reward money to find whoever killed the two students, after more funds were pledged on April 17. Los Angeles has a large Chinese and Chinese-American population, including many overseas students and certain areas of the city are known for frequent gun violence. AFP PHOTO/Frederic J. BROWN (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)
