Complex sentence: At 10:38 a.m. PDT, the first 9-1-1 call was made from inside the campus, stating a gunman was walking through several campus buildings, shooting people indiscriminately.
Split into simpler sentences: At 10:38 a.m. PDT, the first 9-1-1 call was made from inside the campus. A gunman was reported walking through several campus buildings, shooting people indiscriminately.