Ilia Iaroslavski, the big-billing lawyer who headed the firm's Tashkent office in Uzbekistan, resigned from the firm because of ill health.
A Camerons spokesman says he has since suffered a heart attack and is receiving treatment in Israel.
Iaroslavski first offered to resign from the firm in May 1998 following allegations of sexual harassment made by Veronica Pescud, a secretary in the CIS group.
The firm stood by him then but postponed his promotion to partner. Further harassment allegations were made against Iaroslavski in July 1998 by Natasha Lobova, an assistant in the CIS group.
Following a string of tribunal claims against Camerons from former members of the group, The Lawyer revealed on 10 January that Tashkent State University had no record of Iaroslavski having studied there for the masters in law he claimed to hold.
Camerons would not reveal the exact date on which Iaroslavski resigned but sources say he was called back from leave on the day The Lawyer's story appeared and has not been seen at the firm since.
Following The Lawyer's report, the university has carried out a second painstaking inquiry into the matter, which again showed no record of Iaroslavski having attended the institution.
Camerons says its "urgent inquiries" into the status of Iaroslavski's qualifications are continuing