The US Air Force on Thursday said it had removed its assistant vice chief of staff, Lieutenant General John Hesterman, after an investigation showed he had engaged in an unprofessional relationship with a married female Air Force officer about five years ago.Hesterman, who previously commanded the U.S. Air Force component of U.S. Central Command, gave up his duties Thursday and submitted a retirement request, the Air Force said in a statement. It said it was still reviewing whether to downgrade Hesterman's rank for engaging in an unprofessional relationship with a lower-ranking officer, and for engaging in conduct unbecoming an officer and gentleman."These e-mail exchanges were found to have constituted an unprofessional relationship. The investigation did not uncover any additional misconduct," the Air Force said.The Air Force said a third allegation was not substantiated; that section of the report was completely redacted.The anonymous complaint that triggered the probe alleged that Hesterman also interfered in the military assignments of the female officer's former husband, according to a heavily redacted copy of the investigation report.The Air Force said it could not comment on any disciplinary action regarding the female lieutenant colonel, a reserve officer serving in a full-time position, since that process was not complete. Neither her name nor the name of her former husband were disclosed.