He was doing experiments that you can only do with a special permissions grant from the DEA. A chemist, he was bestowed with the rights to house and manufacture the chemicals that are on Schedule I (no source, sorry) and later, when it was more convenient for the DEA to discredit him, they drummed up some phony test results showing slightly elevated levels of mercury in the ground around his lab, and used this as an excuse to destroy his lab and revoke his certifications.

I never heard of this person before he died, but I did read about him after that, and he was no friend to a tyrant, let me assure you. Spend some time reading other sources about him if you are really interested, I'm sure the Wiki article as they tend to do paints both pictures, but I think you'll find very few (individual) people with a single mind about him that didn't like him a whole lot.