There was the case when someone was deliberately poisoning Tylenol in Chicago back in 1982, killing 7 people. The man who they think did the poisoning just died

There was the case when someone was deliberately poisoning Tylenol in Chicago back in 1982, killing 7 people. The man who they think did the poisoning just died two months ago, and was never charged. The three different makers of the affected kid's cough medicine in India say they do not use DEG, so how did it manage to be a 34% solution? It sounds pretty similar to me.