Most of the deaths occurred in the spring, when fishers come out to mate and raise their kits, and all of the poisoned animals were found in remote areas but within the vicinity of illegal marijuana farms.
Links
[1] http://www.smithsonianmag.com/science-nature/illegal-pot-farms-are-killing-rare-animals-bacon-scented-poison-180957159/?utm_source=smithsoniandaily&no-ist
[2] http://rethinkpot.org/tags/animals
[3] http://rethinkpot.org/tags/pesticide