In 2012, USC students were expecting to have a good time at an on-campus Halloween party at the Ronald Tutor Campus Center. Instead, what they experienced was a shooting that wounded four people.

Now, the Los Angeles Times reports prosecutors said Wednesday the man -- 21-year-old Brandon Spencer, a non-USC student -- accused of opening fire at that party was retaliating for his being shot by a rival gang member.

Spencer is charged with four counts of attempted murder; Crenshaw High School football star Geno Hall suffered four gunshot wounds, and three other men were shot.

Reportedly, Spencer had a rivalry with Hall that stemmed from gang affiliations. At the USC party, Spencer ran into Hall, they argued and shots were fired.

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