Danny Casolaro seems to have been murdered. According to many reports, prior to his death he had been receiving harassing and threatening phone calls at all hours. He also told his brother that if someone happened to him, it would be foul play. He also apparently hated blood, so likely would not have slit his own wrists.
Conspiracy theorists can fit any size peg into any size whole by selectively chipping away at the peg or fabricating its size to suite the hole. There's always something shadowy and nefarious behind a coincidence to a conspiracy theorist, and more often than not, the closer they feel to the "truth", or the more they inflate the possible shadow dealing, the more paranoid and fearful they become. Casolaro would not be the first "journalist" to stumble on such a "scoop", one that seemed to spiral into madness until their untimely demise. And if speculation is to be believed, Casolaro was so wrapped up in his theories that it would not be beyond imagination for him to have constructed his suicide so as to appear like he was murdered. Given his primary contact in his research was described as a weapons creator, platinum miner, and meth cooker/distributor, I'm not inclined to put a lot of stock by any information that he may have happened upon through that source. Add to that the circumstances of his suicide not being implausible (despite the number of cuts on his arms, if none severed a tendon, they could all have been made by Casolaro himself), and the presence of alcohol, and it just sounds like a sad end to a mad life.