Mitch Harvey was a Starfury pilot, who served on Babylon 5 in Alpha Wing.
In 2259 while in hyperspace, Harvey saw "The Ghost". Though he couldn't get his gun camera around in time to capture an image, his sensors did detect a change in local hyperspace as it went by along with a very unusual trail of neutrino emissions.
Later that year Warren Keffer came to Harvey looking to track down "The Ghost", Harvey was at first reluctant to talk about it but eventually relented and gave Keffer all of the data from his encounter.[1]