For the moment there are lots of unanswered questions, perhaps most importantly: Why are the clothes only being tested eight years after the fact?
When Arafat died there was an avalanche of speculation that it was foul play. My assumption in 2004 was that it wasn't entirely shocking that a 75-year old man, who'd had a hard life and his physical movement restricted by Israel to his compound for the previous two years, would pass away. Conspiracy theories are popular everywhere, certainly nowhere more so than in the Middle East, and a lot of the speculation about his death struck me as standard point-making from opposing sides.
Many Palestinians were convinced that he'd been poisoned by Israel. In the final years of his life, Arafat had been completely isolated by Israel. In 2002, Israeli troops laid seige to his Muqata headquarters in Ramallah and destroyed all but one of the buildings there with bulldozers. From the point of view of Arafat stalwarts, what could make more sense than Israel finishing off a man they'd come to see as an obstacle in the years since the Oslo accords? And it wasn't as if Israel had been shy about threatening Arafat.
In September 2003 Ehud Olmert, then a member of Prime Minister Ariel Sharon's cabinet, told Israel Radio that killing Arafat "is definitely one of the options" the government was considering. "We are trying to eliminate all the heads of terror, and Arafat is one of the heads of terror," Mr. Olmert, who went on to serve as Prime Minister, said at the time. Arafat was dead a little over a year later.