CG 6632-C* - "PLUMB" mic in Murray Humphreys' Apartment

• This was a mite microphone known as “PLUMB” located in the wall behind the baseboard in apartment 5131, Marina Towers East, Marina City, Chicago, IL per www.maryferrell.org/showDoc.html?docId=168561#relPageId=3
• Believe this began 1963-03-21 per William Roemer book
• Requested to have information summarized by bureau
• This is in Murray Humphrey’s apartment.