A retired Army lieutenant colonel who worked as an Air Force civilian employee has pleaded guilty to conspiring to provide classified information through an online dating app to someone claiming to be a person in Ukraine. On Thursday, 64-year-old David Slater entered his guilty plea, a Justice Department news release said. Slater, after retiring from the Army, was an Air Force employee assigned to U.S. Strategic Command at Offutt Air Force Base , Nebraska, where he held a top security clearance.