DELTA GREEN A VICTIM OF THE ARTA serial killer is at work in quiet Glenridge, Long Island. Bizarre mutilations mark the victims of the Glenridge Chiropractor, as national news and the conspiracy theorists at Phenomen X call the killer. Privately, the medical examiner is more troubled by residue found on the corpses: a pulpy, gray, organic substance that defies analysis. When the police ask the FBI for help, Delta Green agents answer the call. This is hardly the first serial killer