F.B.I. Says Little Doubt North Korea Hit Sony - NYTimes.com

The rest of the story?...

"Responding to critics who have questioned why the United States thinks North Korea was the source of the attacks, Mr. Comey said on Wednesday that the hackers became “sloppy” as they tried to cover their tracks. He acknowledged that the North Koreans had used decoys but did not elaborate about the specific mistakes the hackers made that gave him “high confidence” the country was behind the attack."

F.B.I. Says Little Doubt North Korea Hit Sony - NYTimes.com