F4WOnline.com has independently confirmed that testing positive for steroids in a June drug test was the cause of Sin Cara's suspension from WWE per the terms of the Talent Wellness Program. They date the test failure as having taken place in early June.
It gets a lot more interesting from there: According to the writer of the post (there's no byline but it reads like it's by Dave Meltzer as opposed to Bryan Alvarez), "He may not be brought back."
I'm not sure what to think. Was there something about the positive test and follow-up that led Triple H, Vince McMahon, et al to decide that they had to cut their losses and get rid of him? Could his steroids have been sourced from a Mexican pharmacy and indicative of a habit that they felt couldn't be broken? Was the suspension handled the way it was because they knew they would be letting him go so they'd "kill him off" in a way that puts over the danger of ladder matches? Where does this leave Averno, who was first reported as WWE bound on May 29th, probably a week or so before the drug test? Did he ever officially sign? Is this one of the reasons why Averno is still working full-time in CMLL when most were expecting him to leave right after he dropped his mask a month ago?
Lots of questions, more answers probably coming soon...