Retired agent Joe Wolfinger served nearly 30 years with the FBI. During his Bureau career, he rose through a variety of positions—serving as a squad supervisor, inspector, Special Agent in Charge (SAC), and lastly, as Assistant Director in Charge (ADIC) of the FBI Academy at Quantico, VA. In this episode of FBI Retired Case File Review, Joe Wolfinger is interviewed about his supervision of the counterintelligence squad in Norfolk, VA and the investigation of John Walker, a retired U.S. Navy chief warrant officer and communications specialist who sold secrets about American military codes to the Soviets for nearly 20 years. He also recruited his friend, brother and son and together they caused extensive damage to America's national security. The John Walker spy ring has been described as the "most damaging Soviet spy ring in history. Walker pled guilty and was sentenced to life in prison. For those who want to learn more about the investigation, Joe Wolfinger recommends retired case agent Bob Hunter's book Spy Hunter: Inside the FBI Investigation of the Walker Espionage Case. After retiring from the FBI, Wolfinger served pro bono for fourteen years as the executive director of the Major County Sheriff's Association.