What is the lowest Killed, when Perpetrator is "Sherrill, Patrick Henry , 44"?
CREATE TABLE "workplace_killings" (
  "perpetrator" text,
  "date" text,
  "year" real,
  "location" text,
  "country" text,
  "killed" real,
  "injured" text
);
SELECT MIN("killed") FROM "workplace_killings" WHERE "perpetrator"='sherrill, patrick henry , 44';