Depends on dosage. The anthrax in 2001 got its intended victim, a photography editor for the Globe, while killing just one other person. Infowars is unreliable (why it can’t be used as a source), but occasionally finds an acorn.
I can think of three sources of polonium that wouldn’t be fatal (Russians aren’t on the list). Find dosage (if any), point to motive.
I was thinking of the radioactive Polonioum used to poison that one fellow.