The unit was connected with the NATO Headquarters. In May 1987, he returned home again. Due to his top performance, he was selected for attendance at a training school. Following graduation in February 1988, he was promoted to the rank of warrant officer and was assigned to intelligence staff (G-2) at the 24th Infantry Division in Fort Stewart, west of Savannah, Georgia. The units, in which he served throughout his career, engaged in cryptographic analysis, electronic intelligence (ELINT), voice interception, communications intelligence (COMINT), and electronic warfare (EW). During his service time in Frankfurt, at a unit  Hall had access to even most sensitive top secret NOFORN documents, any information that is higher classified than NATO documents, and may not be released to any non-U.S. citizen. He was an enlisted serviceman in the U.S. pay grades of E-5 and E-6 during his time in West Berlin. His last salary as a warrant officer amounted to US$25,894, including benefits. Hall married a German woman named Heidi, who bore him two daughters. Peggy Bie was an American organist who traveled to West Berlin to do research work on her doctoral thesis. As an Army widow, she had access to the army auto craft shop where Yıldırım worked. She frequented the auto craft shop to learn more about auto repair for her shabby vehicle. Bie and Yıldırım got closer in 1985, became good friends, and soon started a romance. Yıldırım left his wife and two children in West Berlin and began living together with Bie in Wedding, Berlin. When Bie returned to Tampa, Florida, where she had a beach house, Yıldırım quit all his ties in Germany and followed her. She sponsored his immigration to the United States and they settled in Belleair Beach, Florida. There, Yıldırım took care of Peggy's mother, who suffered from Alzheimer's disease. While working in Stuttgart, Yıldırım applied in 1978 to East Germany's Ministry for State Security (, MfS), commonly known as the Stasi, offering his spying services. Not interested in an industrial plant, the Stasi advised him to contact them later when he had information on military subjects. Yıldırım contacted the Stasi again in 1979 and told about his new status in West Berlin. He was welcomed by the organization, though it took some time for him to be registered as an unofficial staff member (Stasi jargon , IM) under the code name "Blitz", which took place on May 12, 1980.