Complex sentence: Following the War, Hays left the FBI and briefly worked for the San Bernardino Sun as reporter before joining the Press-Enterprise in 1946 as an assistant editor under his father, Howard H. Hays, Sr, who was editor and co-owner of the paper.
Split into simpler sentences: Following the War, Hays left the FBI and briefly worked for the San Bernardino Sun as reporter. He then joined the Press-Enterprise in 1946 as an assistant editor under his father, Howard H. Hays, Sr, who was editor and co-owner of the paper.