Cryptonym: WOMUSE
https://www.archives.gov/files/iwg/declassified-records/rg-263-cia-records/second-release-lexicon.pdf
WOMUSE is defined as the "CIA Counterintelligence Center".
CounterIntelligence chief James Angleton's office was the primary department of CIA involved in the post-assassination investigation. This document forwarding six volumes of material on Oswald from Mexico City's CIA station to "Chief, WOMUSE/R&A", indicates a likelihood that WOMUSE is CIA's CounterIntelligence division.
1993.06.19.09:22:09:250000: CHRONOLOGICAL LISTING OF ITEMS PREPARED BY SR/CI/RESEARCH ON THE OSWAL
5/5/65 memo: WOMUSE is almost certainly the agency that put together this chronology on all the post-assassination items about Oswald prepared by SR/CI/Research (this may have been Lee Wigren's work) and provided to the Warren Commission.
104-10052-10137: KENNEDY ASSASSINATION REPORT ON OSWALD'S TRIP TO MEXICO CITY
This document regarding a new allegation about Oswald surfacing in 1967 states "We are coordinating closely in this matter with WOMUSE."
Chief, WOMUSE is the source of this dispatch to CIA stations and bases providing guidance around Presidential protection during visits abroad.
104-10172-10384: CABLE RECAP OF BROWN CASE: LOCAL POLICE HAVE GENUINE INTEREST
9/13/67, WAVE memo, with WOMUSE slugline: The word is that Brown may be heading to Chicago, and has been talking with the Hemming group, i.e. Martin Casey, Joe Gorman, and Joe (?) Collins.