A senior Air Force general who ran the aerial campaign against ISIS has been fired from his job and will retire after an investigation found that he had an unprofessional relationship with a lower-ranking female officer.

The Air Force said Thursday that Lt. Gen. John Hesterman, the assistant vice chief of staff, was found guilty of misconduct for emails he exchanged with an Air force lieutenant colonel between March 2010 and May 2011.

The investigation found that the emails included language that was "sexually suggestive in places and romantic in other places." 

One of Hesterman's emails signed off with "much love" In another he talked about wanting to see her, saying "I've missed you my lovely girl."

Hesterman told investigators that he didn't recall some of the exchanges and that he didn't remember being that friendly.

The Air Force said the investigation did not recover any additional misconduct by Hesterman.

Fox News' Lucas Tomlinson and The Associated Press contributed to this report.