Complex sentence: Further complicating the investigation is Christina's continuous flirtations with David, a distraction David gladly welcomes but older brother, Robert (Anthony Andrews), is adamantly against, revealed as having an incestuous relationship with Christina.
Split into simpler sentences: Further complicating the investigation is Christina's continuous flirtation with David, a distraction he gladly welcomes. However, older brother Robert (Anthony Andrews) is adamantly against their friendship, and is revealed as having an incestuous relationship with Christina.