Who is Paul Stevens from Plum Island and what is their importance?

Paul Stevens is the Director of Security for Plum Island Research Facility, and unbeknownst to the Gordons, was involved in the scheme to steal the treasure from Plum Island. He is described as a cold man with a professional appearance. When Stevens and John fight in Stevens' backyard, the true character of Stevens comes out, and John knows the man is involved in the murders in some way. At Plum Island, the tension heightens when Stevens encounters John and is killed by Beth before Stevens can kill John.