The truth, as always, isn't quite the same as what you read in the tame corporate media (and, yes, Slashdot does fit that description).
In fact, the author of that article died in a car accident three days after it ran. The Seattle police claim that there was "no evidence of foul play", but there was no autopsy and the body was cremated within a week, which some observers think was a bit hasty. There are been a number of requests for an in-depth investigation from concerned citizens, but the police insist that these people "have no standing", that there is "no evidence of anything", etc. etc. The usual story. Of course there's no evidence; the police haven't looked for any. Without an investigation, doubts will remain, and rightly so.
There are a lot of unanswered questions. As usualy, the media are not even asking them.