Scientists don't usually test for cyanide in the battery of toxicology tests they may run in a suspicious death and don't generally look for it unless there is a reason to suspect it.

CNN: Lottery winner exhumed; cyanide deaths rare, experts say

In this next step in the investigation, scientists will examine Khan's brain, the liver and even solid organs to try and detect the presence of cyanide so they have more than one test showing it's what killed him -- and a better sense of how it was introduced into his body.

CNN: Lottery winner exhumed; cyanide deaths rare, experts say