Dr. Aaron Baker worked in an abortion clinic in Syracuse, New York. He was the fourth of five abortion doctors who was killed by the alien bounty hunter. Mulder became involved in finding Dr. Baker after the deaths of Dr. Prince, Dr. Buchanon, and Dr. Gayhart, all abortion doctors that died in separate arson fires. After talking to suspect, Calvin Sistrunk and through a newspaper clipping, Mulder and Scully learn that someone had put out an ad to locate Dr. Landon Prince.