The Post reports that James E. Swann, Jr. — the notorious “Shotgun Stalker” who killed four people and injured five others during a two-month-long rampage around Mount Pleasant and Columbia Heights in 1993 — has been denied a temporary release from St. Elizabeth’s Hospital. The 46-year-old Swann, who has resided at St. Elizabeth’s since being declared not guilty by reason of insanity during his 1994 murder trial, was diagnosed as still suffer from schizophrenia and…