Indeed. But there are other explanations for such such signs and symptoms as well.

The facts are that Mark had no reported history of drug abuse. No evidence for it was reported by the autopsy. No sign of it in the extensive pre expedition investigations which screen people very, very carefully. The chance of a past or present IV drug user wintering over at the South Pole are probably about the same as one becoming an astronaut.

He died of methanol poisoning, not IV drugs. Thy could have been self administered, accidently adminstered, or malicously administered. In the first case the base crew should have identified a problem and manged it better. In the second there is and OH&S problem that could endanger others, in the third there is a murder out there why may well winter over again. This is what makes the lack of cooperation with the inquiry by the NSF very serious.

Jon