Complex sentence: John reacts quickly, killing the officer and dumping his body by the side of the road before departing for Washington DC where he intends to infiltrate Stephenson's inner-cirlce by passing himself off as the cousin of the vice-president's wife, Laura.
Split into simpler sentences: John reacts quickly, killing the officer and dumping his body by the side of the road. He then departs for Washington DC where he intends to infiltrate Stephenson's inner-cirlce by passing himself off as the cousin of the vice-president's wife, Laura.