In October 1966, a friend informed her that a CIA recruiter was on campus.
He told her she "would make a perfect spy."
She pursued this due to the fact she desperately needed a job before graduation.
Following her interview with the CIA, she was given a position as a GS-06 Intelligence Assistant for which she needed to have security and medical clearances before she could get unrestricted access.
When she reported for duty at the Ames building in Rosslyn, Virginia, she and her fellow co-workers became clerical employees.

Grimes' first job was working in the Soviet Bloc Division of the Directorate of Operations, which included the intelligence from then Colonel Dmitri Fedorovich Polyakov.
She trained herself to become familiar with Soviet intelligence services, during which she used index cards to track counterintelligence and positive intelligence.

In Fall 1968, Grimes attended operations training and met SE Division expert Dick Kovich.
In 1970, she eventually was granted an interview  for conversion to professional status and afterward worked her way up and was given the duty of replacing a senior intelligence analyst in the Branch.
She later became a Soviet and Eastern European Division officer and remained with their counterintelligence group for eleven years, holding various titles and positions.
It was through this experience that she gained knowledge of the KGB and the GRU.
During this time.
Grimes worked or assisted in cases which included Aleksey Isidorovich Kulak and Leonid Georgiyevich Poleshchuk.

In the late 1970s, through an organizational change in the CI group, she met Jeanne Vertefeuille.
Together with Faith McCoy, Grimes and McCoy made a proposal to create two branches in the CI group, both of which to handle CI dissemination and production in a specific geographical region.
One would deal with the Soviet bloc and the other the Eastern European bloc.
Eventually, the two branches merged, where Vertefeuille was the chief and Grimes became the Soviet section chief.

In 1981, after 14 years in CI, Grimes moved to the Career Management Staff after a change in feelings.

In early 1983, she eventually moved on to becoming deputy chief of external operations in Africa and two weeks later became acting chief.
In early 1984, Grimes was appointed permanent Chief of SE External Operations for Africa.

After the arrest of then General Poleshchuk on October 2, 1985, in January 1986, Grimes was part of the attempt to stop CIA assets from being exposed, which was an extraordinary "back room" security procedure.
This role was in addition to Grimes' role of Chief of SE External Operations for Africa.

She was eventually brought into a CIA operation in Bonn.
An anonymous write-in, involving a person named Mister.
X, mentioned that the Soviet sources of the CIA were compromised due to a penetration of the CIA communications.
The author demanded $50,000 in a cache or dead drop in East Berlin.
In March 1987, Grimes was transferred from her position in Africa and was assigned to the Moscow Task Force.
Moscow Embassy Marine Guard Arnold Bracy and Clayton Lonetree allowed the KGB entry to the secure areas within the U.S. Embassy.

In 1989, Grimes moved from being Chief of the Production Branch to a part-time position in the Special Projects Section.
In early 1991, she was working on GTPROLOGUE when she was offered the assignment to investigate the 1985 loss of Polyakov and others.

During a joint mole-hunt, Grimes was a member of the team who made the first breakthrough in 1992.
She correlated times that Ames met with Sergey Dmitriyevich Chuvakhin, his KGB contact, with times that he made large bank deposits in 1985 and 1986.

In early 1993, Grimes resigned from the CIA.
In October 1966, a friend informed her that a CIA recruiter was on campus. He told her she "would make a perfect spy." She pursued this due to the fact she desperately needed a job before graduation. Following her interview with the CIA, she was given a position as a GS-06 Intelligence Assistant for which she needed to have security and medical clearances before she could get unrestricted access. When she reported for duty at the Ames building in Rosslyn, Virginia, she and her fellow co-workers became clerical employees. 
Grimes' first job was working in the Soviet Bloc Division of the Directorate of Operations, which included the intelligence from then Colonel Dmitri Fedorovich Polyakov. She trained herself to become familiar with Soviet intelligence services, during which she used index cards to track counterintelligence and positive intelligence. 
In Fall 1968, Grimes attended operations training and met SE Division expert Dick Kovich. In 1970, she eventually was granted an interview  for conversion to professional status and afterward worked her way up and was given the duty of replacing a senior intelligence analyst in the Branch. She later became a Soviet and Eastern European Division officer and remained with their counterintelligence group for eleven years, holding various titles and positions. It was through this experience that she gained knowledge of the KGB and the GRU. During this time. Grimes worked or assisted in cases which included Aleksey Isidorovich Kulak and Leonid Georgiyevich Poleshchuk.
In the late 1970s, through an organizational change in the CI group, she met Jeanne Vertefeuille. Together with Faith McCoy, Grimes and McCoy made a proposal to create two branches in the CI group, both of which to handle CI dissemination and production in a specific geographical region. One would deal with the Soviet bloc and the other the Eastern European bloc. Eventually, the two branches merged, where Vertefeuille was the chief and Grimes became the Soviet section chief.
In 1981, after 14 years in CI, Grimes moved to the Career Management Staff after a change in feelings.
In early 1983, she eventually moved on to becoming deputy chief of external operations in Africa and two weeks later became acting chief. In early 1984, Grimes was appointed permanent Chief of SE External Operations for Africa. 
After the arrest of then General Poleshchuk on October 2, 1985, in January 1986, Grimes was part of the attempt to stop CIA assets from being exposed, which was an extraordinary "back room" security procedure. This role was in addition to Grimes' role of Chief of SE External Operations for Africa.
She was eventually brought into a CIA operation in Bonn. An anonymous write-in, involving a person named Mister. X, mentioned that the Soviet sources of the CIA were compromised due to a penetration of the CIA communications. The author demanded $50,000 in a cache or dead drop in East Berlin. In March 1987, Grimes was transferred from her position in Africa and was assigned to the Moscow Task Force. Moscow Embassy Marine Guard Arnold Bracy and Clayton Lonetree allowed the KGB entry to the secure areas within the U.S. Embassy.
In 1989, Grimes moved from being Chief of the Production Branch to a part-time position in the Special Projects Section. In early 1991, she was working on GTPROLOGUE when she was offered the assignment to investigate the 1985 loss of Polyakov and others.
During a joint mole-hunt, Grimes was a member of the team who made the first breakthrough in 1992. She correlated times that Ames met with Sergey Dmitriyevich Chuvakhin, his KGB contact, with times that he made large bank deposits in 1985 and 1986.
In early 1993, Grimes resigned from the CIA.
Sandra Grimes