While riding around his North Yorkshire estate on a Segway, [Jimi Heseldon] reportedly drove straight off a cliff and into the River Wharfe. A spokesperson for West Yorkshire police confirmed his death: “He was pronounced dead at the scene.”
source <--- warning, web site may be poorly behaved
Heseldon did not invent the Segway, he just bought the company last year. His company was primarily engaged in defense contracting.