They called it the Halloween Massacre, in the fall of 1977 when CIA Director Stansfield Turner fired about 200 CIA employes in an abrupt economy move. Today some of those fired are finishing books about their years with the agency. But one agent who didn't ask to be brought in from the cold wants to make his former employer uncomfortable another way: he intends to file a class action suit claiming the firings represented age discrimination.

Bill O'Brien of McLean served in Vietnam, Thailand, Copenhagen and was working as an operations officer in Los Angeles when he received his pink slip. After applying for about 200 jobs -- "The CIA is sort of a dirty word," says O'Brien -- he finally landed a job as sales representative for Burns International Security Services, the rent-a-cop company.

"A very high percentage of those fired were over 40," says O'Brien, who is 45 and was less than six years away from being eligible for retirement. He is still waiting to learn the results of an internal appeal for reinstatement on grounds of age discrimination, but he is pessimistic. So O'Brien and attorney Michell Rogovin say they intend to file a class action suit on behalf of other ex-agents who share O'Brien's quandary. Ex-agents have begun contributing to a legal war chest named after O'Brien's nickname, the "OB Legal Fund."

Footnote: Attorney Rogovin once represented William Colby during the former CIA director's Capitol Hill appearances.