Something might not add up.
They found Polonium in his body. Does this mean he was poisoned, or does it mean someone somewhere along the line was working with a dirty bomb? This is something found in nuclear reactors, and was used in the making of the first atomic bombs dropped on Japan. It's also been commonly used to poison people.
Polonium also is found in small amounts all around us such as photographic plates, textile mills, paper rolls, sheet plastics, and on substrates prior to the application of coatings (such as automotive). (
Got that bit from Wikipedia.)
Not saying he wasn't poisoned - lots of people wanted him dead. I'm just saying it could have been a poisoning, someone working with a dirty bomb, or the fact that he painted a car in his garage without wearing a mask.