People who knew Aaron Traywick, the biohacker who died last month at a spa in Washington, D.C., were initially suspicious about the circumstances of his death.

David Ishee, a researcher for Mr. Traywick’s company, Ascendance Biomedical, said his first thought upon hearing that Mr. Traywick’s body had been discovered in a sensory deprivation tank was that he had faked it and run off with his clients’ money.

Tristan Roberts, another biohacker who worked with Ascendance, thought the same thing. Maybe the body was just “a very convincing clone,” he joked.

Kelly Martin, who helped found Ascendance Biomedical , had a different theory, one that hinted at a conspiracy. “There’s speculation, if you watch Aaron’s last video, that he was going to provide disruptive technology that would upend Big Pharma,” she said. “He said that we were close to coming up with something that was pretty revolutionary.”