He was said to have been wearing a grey baseball cap with a peak worn at the back, a black T-shirt with a Nike logo on the left breast and black tracksuit bottoms, worn low on his hips.
One, who may have run with a slight limp, was wearing a baseball cap with a cream or white peak, a light blue hip-length hooded jacket and reflective strips down the sleeves.
He retired in 1999 at the peak of Microsoft's market cap, bought a used Gulfstream III jet and invested his nine-figure fortune in dinosaur fossil hunts and the like.